
[Cancer Research 60, 2155-2162, April 15, 2000]
© 2000 American Association for Cancer Research
Complete Sequencing of TP53 Predicts Poor Response to Systemic Therapy of Advanced Breast Cancer1
Els M. J. J. Berns2,
John A. Foekens,
Rolf Vossen,
Maxime P. Look,
Peter Devilee,
Sonja C. Henzen-Logmans,
Iris L. van Staveren,
Wim L. J. van Putten,
Mats Inganäs,
Marion E. Meijer-van Gelder,
Cees Cornelisse,
Cassandra J. C. Claassen,
Henk Portengen,
Bert Bakker and
Jan G. M. Klijn
Department of Medical Oncology, Division of Endocrine Oncology [E. M. J. J. B., J. A. F., S. C. H-L., M. P. L., I. L. v. S., M. E. M-v. G., C. J. C. C., H. P., J. G. M. K.] and Department of Statistics [W. L. J. v. P.], Rotterdam Cancer Institute (Daniel den Hoed Kliniek)/University Hospital Rotterdam, 3008 AE Rotterdam, the Netherlands; Departments of Human and Clinical Genetics [R. V., P. D., B. B.] and Pathology [C. C.], Leiden University Medical Center, Leiden 2300, the Netherlands; and Amersham Pharmacia Biotech, Upsala, Sweden [M. I.]
 |
ABSTRACT
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TP53 has been implicated in regulation of the cell cycle,
DNA repair, and apoptosis. We studied, in primary breast tumors through
direct cDNA sequencing of exons 211, whether TP53 gene
mutations can predict response in patients with advanced disease to
either first-line tamoxifen therapy (202 patients, of whom 55%
responded) or up-front (poly)chemotherapy (41 patients, of whom 46%
responded). TP53 mutations were detected in 90 of 243
(37%) tumors, and one-fourth of these mutations resulted in a
premature termination of the protein. The mutations were observed in
32% (65 of 202) of the primary tumors of tamoxifen-treated patients
and in 61% (25 of 41) of the primary tumors of the chemotherapy
patients. TP53 mutation was significantly associated
with a poor response to tamoxifen [31% versus 66%;
odds ratio (OR), 0.22; 95% confidence interval (CI), 0.120.42;
P < 0.0001]. Patients with
TP53 gene mutations in codons that directly contact DNA
or with mutations in the zinc-binding domain loop L3 showed the lowest
response to tamoxifen (18% and 15% response rates, respectively).
TP53 mutations were related, although not
significantly, to a poor response to up-front chemotherapy (36%
versus 63%; OR, 0.34; 95% CI, 0.091.24). In
multivariate analysis for response including the classical parameters
age and menopausal status, disease-free interval, dominant site of
relapse, and levels of estrogen receptor and progesterone receptor,
TP53 mutation was a significant predictor of poor
response in the tamoxifen-treated group (OR, 0.29; 95% CI, 0.130.63;
P = 0.0014). TP53-mutated
and estrogen receptor-negative (<10 fmol/mg protein) tumors appeared
to be the most resistant phenotype. Interestingly, the response of
patients with TP53 mutations to chemotherapy after
tamoxifen was not worse than that of patients without these mutations
(50% versus 42%; OR, 1.35, nonsignificant). The
median progression-free survival after systemic treatment was shorter
for patients with a TP53 mutation than for patients with
wild-type TP53 (6.6 and 0.6 months less for
tamoxifen and up-front chemotherapy, respectively). In conclusion,
TP53 gene mutation of the primary tumor is helpful in
predicting the response of patients with metastatic breast disease to
tamoxifen therapy. The type of mutation and its biological function
should be considered in the analyses of the predictive value of TP53.
 |
INTRODUCTION
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TP53, a tumor suppressor gene, has been shown to have prognostic
value in patients with breast cancer. A few studies with conflicting
results on its predictive value have been published. Endocrine
treatment and chemotherapy improve the survival of women with (primary
or advanced) breast cancer. The antiestrogen tamoxifen is one of the
major compounds used for the endocrine treatment of breast cancer. It
is effective in about one-third of all patients with metastatic disease
and in about 50% of those breast cancer patients that are
ER3
positive. Like chemotherapeutic agents, tamoxifen may cause DNA damage
(1)
. TP53, by regulating response to DNA damage, is a key
element in DNA repair. This tumor suppressor gene has also been
implicated in the regulation of normal cell growth and division, gene
transcription, genomic stability, apoptosis, and senescence. Mutations
in the TP53 gene (also known as P53) are the most frequent
genetic changes found in human breast cancer. Mutation is often
accompanied by deletion of the second allele, resulting in the
elimination of wild-type TP53 activity. P53 protein accumulation, which
often results from TP53 gene mutation, can be measured with
immunological techniques, i.e., IHC or LIA/ELISAs on tumor
extracts.
In two studies on patients with metastatic breast cancer (including 92
and 205 patients, respectively), no significant relation between
immunohistochemically assessed P53 expression and response to endocrine
treatment was observed (2
, 3)
, whereas in another study
(on 17 patients), P53 overexpression was associated with a poor
response to endocrine therapy (4)
. Recently, we have shown
a significant relation between P53 accumulation, as measured by a LIA,
and poor response to tamoxifen therapy in a series of 401 patients
(5)
. Moreover, the existing data on TP53 do not clarify
its capability to predict resistance to chemotherapy for advanced or
recurrent breast cancer (6, 7, 8, 9)
. Furthermore, the data on
its predictive role in the adjuvant setting are conflicting as well
(10, 11, 12, 13, 14, 15, 16)
. Studies on the predictive value of TP53 are
hampered by a number of methodological issues including immunological
versus molecular biological analyses, use of different
cutoff levels in the immunohistochemical analyses, or selection of
patient groups.
About 20% of the TP53 gene mutations do not result in p53
protein accumulation, whereas, on the other hand, p53 accumulation may
also occur without a gene mutation. Therefore we have studied
TP53 gene mutations in a relatively large series of 243
patients with advanced disease. Analysis of the various mutations
allowed us to investigate the biological significance of particular
mutations, which may eventually aid in selecting those aberrations that
could be of predictive value in breast cancer. We show that
TP53 gene mutations predict a poor response to first-line
tamoxifen therapy and probably to chemotherapy in advanced
breast cancer. In an exploratory subset analysis, we also observed that
mutations in one zinc-binding domain, i.e., loop L3, or in
codons that directly contact DNA were related with an even poorer
response to tamoxifen.
 |
PATIENTS AND METHODS
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Assays of Cell Biological Factors
Sequence-based Analysis of TP53.
cDNA-based sequencing was used essentially as described by Bergh
et al. (14)
, Sjögren et al.
(17)
, Kressner et al. (19)
and Falette et al. (20)
. Frozen
untreated primary tumor samples were verified histologically for the
presence of tumor cells, and only those samples containing more than
20% tumor cells were included in our study. mRNA was prepared from the
frozen samples under stringent conditions to avoid degradation and
contamination, and cDNA was generated. TP53 was amplified from the
tumor cDNA by PCR using four sets of overlapping primers (one primer in
each pair was biotin-labeled) to cover the complete protein coding
region (exons 211) of the TP53 cDNA. Solid-phase
sequencing was carried out using Autoload solid-phase sequencing combs
and T7 DNA polymerase (Amersham Pharmacia Biotech). Samples were
analyzed on an automated laser fluorescence DNA sequencer (Amersham
Pharmacia Biotech). Sequence gels and sequences were evaluated with
Sequence Evaluator and Mutation Analyzer software (Amersham Pharmacia
Biotech). All mutations were confirmed by reamplifying the relevant
cDNAs and sequencing the new PCR products.
Assays of ER and PgR.
ER and PgR levels were determined in cytoplasmic extracts (cytosols)
prepared routinely according to procedures recommended by the European
Organization for Research and Treatment of Cancer Breast Cancer
Cooperative Group with ligand binding assays or enzyme immunoassays
(ER-EIA and PgR-EIA; Abbott Laboratories, IL), as described
previously (20)
.
 |
Tumor Samples and Patients
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To evaluate the clinical significance of TP53 gene
alterations in advanced disease, 265 primary breast tumor specimens
were analyzed. Sequence data (protein coding exons 211 of the
TP53 gene) were successfully obtained from 243 tumors (92%;
Table 1
). In five cases, the sequence analysis was incomplete, although a
mutation was observed; these samples were included. For nine cases, the
sequence analysis was incomplete, but no gene mutation was observed;
these nine samples were not included because mutations could not be
excluded. In 13 cases (5%), no PCR product could be generated (in two
separate experiments). Consequently, the analysis with respect to
TP53 mutation and response to systemic therapy was performed
on 243 breast cancer patients who developed recurrent disease. The
patient group in the present study is not identical to the population
described previously, i.e., 165 patients were described
previously (5)
. A total of 202 patients (83%) received
first-line tamoxifen therapy, whereas 41 (17%) patients, especially
younger women with ER-negative tumors, received first-line chemotherapy
for advanced disease.
First-Line Tamoxifen Treatment.
Between 1979 and 1991, 202 patients underwent resection of their
primary tumors (breast-conserving therapy, 67 patients; modified
mastectomy, 132 patients; and biopsy, 3 patients) and were
selected according to the criteria described previously
(21)
. In the first-line tamoxifen-treated group, 20
patients were stage I, 110 patients were stage II, 45 patients were
stage III, and 22 patients were stage IV. With respect to stage, data
on five patients are unknown. Twenty-seven patients (13%) received
systemic adjuvant chemotherapy (CMF, 18 patients; CAF, 9 patients).
Twenty-three patients (11%) were diagnosed with metastatic disease
(M1) at the time of primary surgery. All patients
were treated with 40 mg of tamoxifen daily as a first-line hormonal
therapy after relapse. All patients were tamoxifen naïve and
had not received prior chemotherapy for advanced disease. The median
age of these 202 patients at the start of first-line tamoxifen therapy
was 62 years (range, 2885 years). Additional characteristics are
listed in Table 2
. The median follow-up of patients who are still alive is 81 months
(range, 51123 months) from primary surgery and 44 months (range,
880 months) from the start of tamoxifen treatment. A total of 163
patients have died (median survival time, 20 months). Tumor progression
occurred in most patients (190 of 202 patients, 94%) during follow-up.
Median time to progression was 7.5 months. After tumor progression on
first-line tamoxifen treatment, 70% of the patients were treated with
one or more additional endocrine agents (mostly high-dose progestins),
whereas 117 patients were subsequently treated with one or more
regimens of chemotherapy after development of hormone resistance.
First-Line (Up-Front) Chemotherapy.
Forty-one patients underwent resection of their primary tumors
(breast-conserving lumpectomy, 22 patients; modified mastectomy, 19
patients) between 1983 and 1991. In the up-front chemotherapy group, 6
patients were stage I, 22 patients were stage II, 9 patients were stage
III, and 4 patients were stage IV. After primary surgery, six patients
received adjuvant chemotherapy, and six patients received adjuvant
hormonal therapy. Four patients (10%) were diagnosed with metastasis
at the time of surgery for their primary tumor. As a first-line
treatment for advanced disease, 22 of these 41 patients (54%) received
CMF, 16 of 41 patients (39%) received CAF, 1 of 41 patients received
Adriamycin weekly, and 2 of 41 patients received a platinum-containing
chemotherapy. The median age at start of chemotherapy was 50 years
(range, 2974 years). Additional characteristics are listed in Table 4
. Median follow-up was 33 months (range, 5107 months) from the date
of primary surgery and 12 months (range, 175 months) from the start
of chemotherapy for recurrent disease. Tumor progression occurred in
all but one of the patients (98%) during follow-up after the start of
chemotherapy. Median time to progression was 4 months. After 12 months,
19% of the patients were alive without progression. Response to
systemic treatment was defined by standard Union Internationale Contre
le Cancer criteria as a patient having either CR or PR
or prolonged stable disease of more than 6 months (21
, 22)
.
 |
Statistical Methods
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The associations of TP53 with continuous variables (ER, PgR, age,
and disease-free interval) were studied with a nonparametric test.
Mutation subsets were analyzed with a Wilcoxon rank-sum test. Two-sided
Ps < 0.05 were considered statistically
significant. Logistic regression analysis was used for the analysis of
response to treatment. Cox regression analysis was used for the
analysis of time to treatment failure and overall survival after start
of treatment. Survival curves were generated using the method of Kaplan
and Meier (23)
. TP53 gene status and the
following factors were evaluated in the multivariate regression
analysis: (a) age; (b) menopausal status;
(c) adjuvant therapy; (d) disease-free interval;
(e) the dominant site of relapse (in case of multiple sites,
the site with the worst prognosis was considered dominant);
(f) ER; and (g) PgR. TP53 was added to this
model.
 |
RESULTS
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TP53 Gene Mutations.
We have sequenced the entire open reading frame of the TP53
gene (exons 211). Mutations were detected in 90 of the 243 (37%)
samples, 9 of which (10%) were observed outside the sequence-specific
DNA binding domain (codons 102292). Fifty of these 90 mutations
(56%) were restricted to the conserved region. Within the zinc-binding
domain regions L2 and L3 (residues 163195 and 236251,
respectively), 31 (34%) mutations were found. Moreover, we observed 15
mutations in four of the seven amino acids important in direct DNA
binding (i.e., codons 241, 248, 273, and 280). As expected,
the majority of the mutations were transitions, and the amino acid
arginine was altered most frequently. Of all 90 mutations, 62 (69%)
were missense mutations, including 3 complex mutations and 1 tandem
mutation. In total, these amount to 42 different changes. The remaining
28 mutations (referred to as non-missense mutations) were 5 in-frame
deletions/insertions, 11 nonsense mutations leading to a stop codon,
and 12 out-of-frame deletions/insertions causing a premature stop
codon. These latter "null mutations" were localized mainly in exon
6. These results imply that one-fourth of the mutations detected in
this study would not result in an increased expression of the TP53
protein, i.e., false negatives.
Patient and tumor characteristics are summarized in Table 1
. The
prevalence of TP53 gene mutations is highest in tumors from
younger women (<40 years of age), in patients who experienced a
shorter disease-free interval, and in ER- or PgR-negative (<10 fmol/mg
protein) tumors. The median ER levels are about 10 times lower in the
tumors with mutations than in those without a TP53 gene
mutation (15 versus 144 fmol/mg protein, respectively).
Menopausal status and prior adjuvant therapy were not significantly
related to TP53 gene mutation. Interestingly, if the primary
tumor had a TP53 mutation, the metastases more often
developed in soft tissue (50%) or visceral tissues (46%) than in bone
(26%) as the dominant site of disease. In an exploratory analysis, we
observed a relatively low ratio between missense and nonmissense
mutations in the primary tumor of patients who developed a relapse in
soft tissue (ratio, 1.4) when compared with the ratios in patients who
relapsed to bone or visceral tissues (ratios, 3 and 3.5, respectively)
as the first site of relapse.
TP53 Gene Mutations and Response to Tamoxifen.
We observed a mutation in 65 of 202 (32%) primary tumor samples,
and this resulted in a premature termination of the protein in 13 of
these 65 samples (20%). Of the 202 patients, 55% responded to
first-line tamoxifen therapy (10 CRs, 25 PRs, and 76 cases of stable
disease). Very young patients (<40 years) tended to have a lower
response rate (33%; Table 2
). Furthermore, the presence of bone or
visceral metastasis, a short disease-free interval after primary
surgery, and low ER and PgR levels were significantly associated with
low response rates to tamoxifen, whereas prior adjuvant therapy showed
no relation with response (Table 2)
. Sixty-six percent of the patients
without a TP53 mutation responded to tamoxifen, whereas only 31% of
the patients with a TP53 mutation responded to tamoxifen therapy (OR,
0.22; P < 0.0001; Table 2
). There was no
significant difference between the response percentages of either
missense or nonmissense mutations (29% and 38%, respectively). The
TP53 gene mutations were stratified according to the type of
mutation, i.e., mutations in the zinc-binding domains L2 and
L3 of the protein, or by residues that directly contact DNA in an
exploratory analysis. Five of 12 (42%) patients with mutations
in L2 but only 2 of 13 (15%) patients with mutations in L3 or 2 of 11
(18%) patients with mutations in codons that directly contact DNA
showed a response compared to a response of 66% in patients with a
wild-type TP53 gene.
Multivariate Analysis for Response to Tamoxifen.
The independent relationship of the variables with response to
tamoxifen therapy for advanced disease was studied using multivariate
logistic regression analysis. TP53 gene mutation status (as
a dichotomized variable) was added to the classical variables (see
Table 2
). Disease-free interval, dominant site of relapse, and ER and
TP53 status were significant in this multivariate analysis. There was
no statistically significant interaction between TP53 mutation and ER
levels.
Response in Clinically Relevant Subsets of Patients Stratified by
ER and PgR Status.
We explored the association of TP53 gene status with
response to tamoxifen therapy in clinically relevant subgroups. Subsets
of tumors from patients with low ER levels (<10 fmol/mg protein,
median survival of the patients = 16 months; see Table 2
), intermediate ER levels (
10 fmol/mg protein but <75 fmol/mg
protein, median survival of the patients = 23 months),
and high ER levels (>75 fmol/mg protein, median survival of the
patients = 30 months) were created. In all three
subgroups, according to ER status, the response rate was better in
patients with wild-type TP53 in their primary tumors. The worst overall
response was observed in patients with ER-negative and TP53-mutated
tumors (n = 23), of whom only 22% responded.
The best response was observed in the patients with high ER levels and
wild-type TP53 in their primary tumors (n = 90), of whom 73% responded.
Relationship Between P53 Mutation and PFS after the Start of
Treatment.
Duration of response is perhaps as important as time to treatment
failure because the duration of response contributes directly to the
quality and duration of life. Using Cox univariate regression analysis,
we observed that the presence of a TP53 gene mutation was
significantly associated with a shorter duration of response (16
versus 11 months; P = 0.0006) in
111 patients who responded to tamoxifen. However, TP53
mutation was not significantly associated with survival after the
start of treatment (40 versus 31 months) in the responders.
The median PFS was shorter for patients with a TP53 mutation as
compared with those with wild-type TP53 (3.0 versus 9.6
months). Patients with TP53 gene mutation in their primary
tumors experienced a shorter PFS and an earlier death (relative hazard
rate, 2.61 and 1.99, respectively, both P < 0.001) than those with TP53 wild-type tumors (see Fig. 1
, ALL). In addition (see Table 2
), younger patients
(age < 40 years) and those with visceral metastasis, a
short disease-free interval, low ER or PgR levels, or TP53 mutation
showed a shorter median overall postrelapse survival after the start of
tamoxifen treatment. In the multivariate analysis for survival after
the start of tamoxifen treatment, the presence of a TP53 mutation was
associated with decreased survival (RHR, 1.39; 95% CI,
0.942.07; P = 0.10).

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Fig. 1. PFS (left) and survival after the start of
tamoxifen treatment (right) as a function of
TP53 gene status in all patients (ALL),
patients with high ER (>75 fmol/mg protein; ER-high),
patients with intermediate ER (10 > ER <75 fmol/mg
protein; ER-medium), and patients with low ER (<10
fmol/mg protein; ER-low). The number of patients below
the X axis represents the number at risk over total
patients in the wild-type and mutated subgroups, respectively.
|
|
We next explored the predictive value of TP53 mutations in subgroups
with low, intermediate, and high ER levels. The relationship between
TP53 status and PFS and overall survival after the start of treatment
was most apparent in the high ER and intermediate ER (Fig. 1
,
ER-medium) subsets of patients but absent in the ER-negative
subset (Fig. 1
, bottom panels).
TP53 Gene Mutations and Response to Chemotherapy.
Of the 113 patients that were evaluable for chemotherapy after
tamoxifen therapy in this study, 51 (45%) responded to chemotherapy (1
CR, 19 PRs, and 31 cases of stable disease). When compared with bone
metastasis and soft tissue, patients with visceral metastasis had the
worst response to chemotherapy after tamoxifen treatment (OR, 0.66). As
shown in Table 3
, patients with TP53 mutations did not respond differently to
chemotherapy after tamoxifen therapy than did patients without
mutations. Stratification according to domain L3 of the protein or by
residues that directly contact DNA (see above) revealed that three of
five patients with mutations in L3 and two of seven patients with
mutations in codons that directly contact DNA showed a response when
compared with an overall response of 42% of patients with the
wild-type TP53 gene.
Of the 41 patients studied with respect to up-front (first-line)
chemotherapy, 19 (46%) responded (4 CRs, 11 PRs, and 4 cases of stable
disease). A relatively high prevalence (61%) of TP53 gene
mutation was observed, i.e., TP53 gene mutation
was observed in 25 of 41 primary tumors. In 10 of these 25 samples
(40%), this resulted in a premature termination of the protein. As
shown in Table 3
, only 36% percent of the 25 patients with a TP53
mutation responded to first-line chemotherapy, in contrast to 63% of
the 16 patients without a TP53 mutation (OR, 0.34). In this exploratory
study on a small number of patients, only menopausal status was
significantly correlated with response to up-front chemotherapy; none
of the other patient and tumor characteristics studied were
significantly correlated with response to up-front chemotherapy.
The median PFS was 3.0 months for those patients with TP53-mutated
tumors versus 3.6 months for patients without TP53 mutation.
 |
DISCUSSION
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The onset and progression of breast cancer is accompanied by
multiple genetic alterations that result in quantitative and
qualitative changes in the expression of these genes. Mutations in the
TP53 gene are the most frequent genetic changes in human
cancer, and, depending on the method of detection, the frequencies of
TP53 mutations reported in invasive breast cancer range from
1246% (24)
. In recent years, numerous reports
have appeared on the relation between TP53 status and (disease-free)
survival, and conflicting conclusions were reached on the prognostic
value of TP53 in breast cancer. The lack of unanimity between authors
may be explained by: (a) differences in techniques used for
the analyses of p53 status (e.g., immunohistochemical
analyses with different antibodies on frozen or paraffin-embedded
tissues using different cutoff levels, ELISA/LIA, PCR-single-strand
conformational polymorphism/constant denaturing gel
electrophoresis analyses of primarily exons 58, or cDNA
sequencing of the entire gene); (b) patient sample size;
(c) subset analyses; (d) retrospective nature of
the studies; (e) different (adjuvant) treatments of the
patient population; (f) different (modern) prognostic
covariates used in the multivariate analyses; (g) the
subjectivity inherent to some approaches; and (h)
publication bias.
Moreover, the relapse tumor could be dissimilar to the primary tumor
because it was shown that TP53 mutations found in the
primary tumors can be absent in the metastasis.
In the present study, we evaluated the predictive value of
TP53 gene mutations, as estimated through cDNA sequencing of
the entire coding sequence of the TP53 gene, in a relatively
large series of breast cancer patients who were treated with tamoxifen
or chemotherapy for advanced disease. We observed TP53 gene
mutations in 32% of the 202 primary tumors of tamoxifen-treated
patients and in 61% of the 41 patients (with mainly ER-negative
tumors) treated with up-front chemotherapy. The observed prevalence is
slightly higher than the mean percentage of 25% [range, 1571%;
examined in 1425 breast tumor samples worldwide; reviewed by Hartmann
et al. (25)
] and a prevalence of 29% [range,
1571%; examined in 16 populations by Soussi (26)
].
This difference can be explained by the fact that the entire coding
sequence of TP53 was investigated and that only those
patients who developed advanced disease were included in the present
study. TP53 gene mutation was related with a poor response
to up-front chemotherapy in our small series of patients (OR, 0.34) and
was similarly but significantly related with a poor response to
first-line tamoxifen treatment in both univariate analysis (OR, 0.22;
P < 0.0001) and multivariate analysis. In
contrast, patients with mutated TP53 in their primary tumors
may respond better to chemotherapy (50% versus 42%) after
tamoxifen treatment, but they did show a shorter PFS and duration of
response.
When evaluating only those reports that have covered TP53 alterations
in relationship with the efficacy of various treatments in breast
cancer, we noticed that there is no agreement on the significance of
the predictive value of TP53. The summary of these 26 studies on almost
6000 breast cancer patients is listed in Table 4
. In 15 reports, there was no significant relation between TP53 status
and type of response (2
, 3
, 6, 7, 8, 9, 10, 11, 12
, 15
, 28
, 30, 31, 32, 33)
,
7 reports described resistance (Refs. 5
, 6 , 14
, 16
, 27
and
29
and this study), whereas the other 4 studies reported
sensitivity (13
, 34, 35, 36)
. However, this survey indicates
that the TP53 genotype, not the immunohistochemical results, is
predictive of response in breast cancer patients: all 5 studies that
used DNA analysis showed a predictive value of TP53, whereas
this was only true in 6 of the 21 immunohistochemical studies,
i.e., 2 studies showed sensitivity, and 4 showed resistance.
Both studies on radiotherapy showed sensitivity to this form of
treatment (34
, 36)
.
The mechanisms that underlie the relationship of p53 alterations and a
poor response to tamoxifen are not clear. Tamoxifen acts as an
antiestrogen via the ER, but some of its effects are thought to be
mediated through the activation of transforming growth factor ß and
by decreasing plasma insulin-like growth factor I levels. Previous data
suggest that the mutant forms of TP53 inhibit the antiproliferative
effect of transforming growth factor ß by interfering with its
signaling pathway. In addition, wild-type TP53 can repress the insulin
receptor and the insulin-like growth factor I receptor promotor in
other cell types. Although the exact mechanisms are unclear, this
complex interplay provides a link between the TP53 gene and
signaling pathways in breast cancer cells (discussed in Ref.
5
). Our finding on the relationship between TP53
gene mutation and poor response to tamoxifen treatment of advanced
disease is well in line with our previous study on p53 protein levels
by LIA in 401 patients with advanced disease (5)
but
disagrees with the studies of Archer et al. (2)
and Elledge et al. (3)
, who assessed p53
expression immunohistochemically and found no relationship with
response to endocrine treatment. Bergh et al.
(14)
and Silvestrini et al. (32)
showed that tamoxifen also appears to be of less benefit in patients
with TP53 gene mutations or overexpression, respectively, in
the adjuvant setting (see Table 4
). The relationship of TP53
gene status with PFS is most apparent in the high ER (>10 fmol/mg
protein) subgroups of our patients. In contrast to our findings,
Elledge et al. (3)
, who studied the
accumulation of p53 using IHC in mainly ER-positive metastatic breast
cancer, did not observe a relation between p53 status and response to
tamoxifen therapy, although they stated that breast tumors with altered
p53 protein are inherently more aggressive, even after they have
metastasized. These conflicting outcomes may again be explained by the
different techniques and study designs.
It is known that some chemotherapeutic agents and ionizing radiation
act by inducing apoptosis in tumor cells. Lowe et al.
(37)
showed that cells expressing mutant TP53 were totally
resistant to apoptosis on treatment, whereas cells expressing the
wild-type gene were sensitive to these therapeutic agents. In the
present study, TP53 gene mutations were related, although
not significantly, to a poor response to up-front chemotherapy (36%
versus 63%; OR, 0.34). However, the number of patients
receiving first-line chemotherapy was small, the regimen is
heterogeneous, and the follow-up was relatively short. Based on this,
it is not possible to draw firm conclusions. Furthermore, we suspect a
better response to chemotherapy after tamoxifen treatment.
Three reported molecular analyses also revealed that TP53
gene mutations predict a response to chemotherapy or adjuvant
radiotherapy in breast cancer patients (6
, 33
, 35)
. In
contrast, all 4 reports on metastatic disease and 7 of 10 reports in
the adjuvant setting revealed no predictive value of TP53 when using
immunohistochemical analyses.
Various mutations can alter the TP53 protein distinctly and lead to
different biological characteristics and tumorigenic potential
(38
, 39)
. L2 and L3 loops of the TP53 gene
contain residues involved in direct DNA contact as well as protein
stabilization. In the present study, those patients with
TP53 gene mutations in codons that directly contact DNA or
with mutations in the zinc-binding domain loop L3 showed the lowest
response to tamoxifen (18% and 15% response rates, respectively).
Survival analyses showed a significantly reduced survival rate for
patients with mutations affecting the zinc-binding domains L2 and L3
compared with patients with mutations outside these regions or with no
mutations (40)
or for patients with mutations affecting
the direct DNA contact (41)
. Moreover, Aas et
al. (6)
showed that mutants affecting the L3 loop
were significantly associated with de novo resistance to
doxorubicin monotherapy in small subsets of patients. Extending the
analysis of these various mutations allows us to focus attention on the
biological significance of particular mutations that may assist the
selection of residues that could be of predictive value in breast
cancer.
IHC is not able to detect every TP53 alteration. In the present study,
we have shown that one-fourth of TP53 mutations found are
"null mutations" that do not lead to TP53 accumulation.
Furthermore, IHC does not us allow to distinguish the
heterogeneity of TP53 mutants. Based on the data from the literature
and the present results, we conclude that the presence of mutation and
the type of mutation have predictive value for response to tamoxifen
treatment. Therefore, we reason that, if tissue resources permit, the
TP53 mutation status should preferably be included in the daily
practice of treatment of metastatic breast cancer patients.
The main conclusion of this study is that TP53 mutation is
significantly associated with a poor response to tamoxifen treatment in
patients with advanced breast cancer. Based on the present results and
the data reviewed, it is tempting to hypothesize that the
TP53 genotype in particular and, to a lesser degree, the
immunohistochemical analysis are predictive of response to therapy in
breast cancer. Prospective studies should be performed to
support this conclusion. Besides mutation analyses, a direct functional
assay (42)
or the measurement of downstream components of
the TP53 pathway such as p21 or MDM2 may confirm the TP53 integrity.
 |
ACKNOWLEDGMENTS
|
|---|
We thank Esfir Lôfman and Nigel Tooke (Amersham Pharmacia
Biotech) and J. Bolt-de Vries, S. E. Binnendijk-Noordegraaf,
and H. Peters (Division of Endocrine Oncology, University Hospital
Rotterdam, Rotterdam, the Netherlands) for excellent technical
assistance.
 |
FOOTNOTES
|
|---|
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
1 Supported in part by Grant DDHK 96-1234 from the
Dutch Cancer Society. 
2 To whom requests for reprints should be
addressed, at Department of Medical Oncology, Josephine Nefkens
Institute, Room Be 424, P. O. Box 1738, 3000 DR Rotterdam, the
Netherlands. Phone: 31-10-4088370; Fax: 31-10-4088377/365. E-mail: Berns{at}bidh.azr.nl 
3 The abbreviations used are: ER, estrogen
receptor; PgR, progesterone receptor; OR, odds ratio, CI, confidence
interval; LIA, luminometric assay; CMF, cyclophosphamide, methotrexate,
and 5-fluorouracil; CAF, cyclophosphamide, Adriamycin, and
5-fluoro-uracil; CR, complete remission; PR, partial remission;
PFS, progression-free survival; IHC, immunohistochemistry. 
Received 10/12/99.
Accepted 2/17/00.
 |
REFERENCES
|
|---|
-
Shibutani S., Shaw P. M., Suzuki N., Dasaradhi L., Duffel M. W., Terashima I. Sulfation of
-hydroxytamoxifen catalyzed by human hydroxysteroid sulfotransferase results in tamoxifen-DNA adducts. Carcinogenesis (Lond.), 19: 2007-2011, 1998.[Abstract/Free Full Text]
-
Archer S. G., Eliopoulos A., Spandidos D., Barnes D., Ellis I. O., Blamey R. W., Nicholson R. I., Robertson J. F. R. Expression of ras p21, p53 and c-erbB-2 in advanced breast cancer and response to first line hormonal therapy. Br. J. Cancer, 72: 1259-1266, 1995.[Medline]
-
Elledge R. M., Green S., Howes L., Clark G., Berardo M., Allred D. G., Pugh R., Ciocca D., Ravdin P., OSullivan J., Rivkin J., Martino S., Osborne C. K. bcl-2, p53, and response to tamoxifen in estrogen receptor-positive metastatic breast cancer: a Southwest Oncology Group study. J. Clin. Oncol., 15: 1916-1922, 1997.[Abstract/Free Full Text]
-
Horne G. M., Anderson J. J., Tiniakos D. G., McIntoch G. C., Thomas M. D., Angus B., Henry J. A., Lennard T. W. J., Horne C. H. W. p53 protein as a prognostic indicator in breast carcinoma: a comparison of four antibodies for immunohistochemistry. Br. J. Cancer, 73: 29-35, 1996.[Medline]
-
Berns E. M. J. J., Klijn J. G. M., van Putten W. L. J., de Witte H. H., Look M. P., Meijer-van Gelder M. E., Willman K., Portengen H., Benraad T., Foekens J. A. p53 protein accumulation predicts poor response to tamoxifen therapy of patients with recurrent breast cancer. J. Clin. Oncol., 16: 121-127, 1998.[Abstract/Free Full Text]
-
Aas T., Børresen A-L., Geisler S., Smith-Sørensen B., Johnsen H., Varhaug J. E., Akslen L. A., Lønning P. E. Specific P53 mutations are associated with de novo resistance to doxorubicin in breast cancer patients. Nat. Med., 2: 811-814, 1997.
-
Niskanen E., Blomqvist C., Franssila K., Hietanen P., Wasenius V-M. Predictive value of c-erbB-2, p53, cathepsin-D, and histology of the primary tumour in metastatic breast cancer. Br. J. Cancer, 76: 917-922, 1997.[Medline]
-
Järvinen T. A. H., Holli K., Kuukasjärvi T., Isola J. J. Predictive value of topoisomerase II-
and other prognostic factors for epirubicin chemotherapy in advanced breast cancer. Br. J. Cancer, 77: 2297-2273, 1998.
-
Rozan S., Vincent-Salomon A., Zafrani B., Validire P., de Cremoux P., Bernoux A., Nieruchalski M., Fourquet A., Clough K., Dieras V., Pouillart P., Sastre-Garau X. No significant predictive value of c-erbB-2 or p53 expression regarding sensitivity to primary chemotherapy or radiotherapy in breast cancer. Int. J. Cancer, 29: 27-33, 1998.
-
Muss H. B., Thor A. D., Berry D. A., Kute T., Liu E. T., Koerner F., Cirrincione C. T., Budman D. R., Wood W. C., Marcos M., Henderson I. C. c-erbB-2 expression and response to adjuvant therapy in women with node-positive early breast cancer. N. Engl. J. Med., 330: 1260-1266, 1994.[Abstract/Free Full Text]
-
Jacquemier J., Penault-Llorca F., Viens P., Houvenaeghel G., Hassoun J., Torrente M., Adelaide J., Birnbaum D. Breast cancer response to adjuvant chemotherapy in correlation with erbB2 and p53 expression. Anticancer Res., 14: 2773-2778, 1994.[Medline]
-
Elledge R. M., Gray R., Mansour E., Yu Y., Clark G. M., Ravdin P., Osborne C. K., Gilchrist K., Davidson N. E., Robert N., Tormey D., Allred D. G. Accumulation of p53 protein as a possible predictor of response to adjuvant combination chemotherapy with cyclophosphamide, methotrexate, fluorouracil, and prednisone for breast cancer. J. Natl. Cancer Inst., 87: 1254-1256, 1995.[Free Full Text]
-
Ståhl O., Stenmark A. M., Wingren S., Rutqvist L. E., Skoog L., Ferraud L., Sullivan S., Carstensen J., Nordenskjold B. P53 expression and the result of adjuvant therapy of breast cancer. Acta Oncol., 34: 767-770, 1995.[Medline]
-
Bergh J., Norberg T., Sjögren S., Lindgren A., Holmberg L. Complete sequencing of the p53 gene provides prognostic information in breast cancer patients, particularly in relation to adjuvant systemic therapy and radiotherapy. Nat. Med., 1: 1029-1034, 1995.[Medline]
-
Degeoges A., de Roquancourt A., Extra J. M., Espie M., Bourstyn E., de Cremoux P., Soussi T., Marty M. Is p53 a protein that predicts the response to chemotherapy in node negative breast cancer?. Breast Cancer Res. Treat., 47: 47-55, 1998.[Medline]
-
Clahsen P. C., van de Velde C. J. H., Duval C., Pallud C., Mandard A-M., Delobelle-Deroide A., van den Broek L., Sahmoud T. M., van de Vijver M. J. p53 protein accumulation and response to adjuvant chemotherapy in premenopausal women with node-negative early breast cancer. J. Clin. Oncol., 16: 470-479, 1998.[Abstract]
-
Sjögren S., Inganäs M., Norberg T., Lindgren H., Holmberg L., Bergh J. The p53 gene in breast cancer: prognostic value of complementary DNA sequencing versus immunohistochemistry. J. Natl. Cancer Inst., 88: 173-182, 1996.
-
Foekens J. A., Portengen H., van Putten W. L. J., Trapman A. M., Reubi J. C., Alexieva J., Klijn J. G. M. Prognostic value of estrogen and progesterone receptors measured by enzyme immunoassays in human breast cancer. Cancer Res., 49: 5823-5828, 1989.[Abstract/Free Full Text]
-
Kressner U., Inganas M., Byding S., Blikstad I., Pahlman L., Glimelius B., Lindmark G. Prognostic value of p53 genetic changes in colorectal cancer. J. Clin. Oncol., 17: 593-599, 1999.[Abstract/Free Full Text]
-
Falette N., Paperin M. P., Treilleux I., Gratadour A. C., Peloux N., Mignotte H., Tooke N., Lofman E., Inganas M., Bremond A., Ozturk M., Puisieux A. Prognostic value of P53 gene mutations in a large series of node-negative breast cancer patients. Cancer Res., 58: 1451-1455, 1998.[Abstract/Free Full Text]
-
Foekens J. A., Look M. P., Peters H. A., van Putten W. L. J., Portengen H., Klijn J. G. M. Urokinase-type plasminogen activator (uPA) and its inhibitor PAI-1 predict poor response to tamoxifen therapy in recurrent breast cancer. J. Natl. Cancer Inst., 87: 751-756, 1995.[Abstract/Free Full Text]
-
Elledge R. M., Lock-Lim S., Allred D. C., Hilsenbeck S. G., Cordner L. p53 mutation and tamoxifen resistance in breast cancer. Clin. Cancer Res., 1: 1203-1208, 1995.[Abstract]
-
Kaplan E. L., Meier P. Nonparametric estimation from incomplete observation. J. Am. Stat. Assoc., 53: 457-481, 1958.
-
Andersen T. I., Borresen A. L. Alterations of the TP53 gene as potential prognostic marker in breast carcinomas. Diagnostics Mol. Pathol., 4: 203-211, 1995.
-
Hartmann A., Blaszyk H., Kovach J. S., Sommer S. S. The molecular epidemiology of p53 gene mutations in human breast cancer. Trends Genet., 13: 27-33, 1997.[Medline]
-
Soussi, T. The p53 tumour suppressor gene: from molecular biology to clinical investigation. In: J. G. M. Klijn (ed.), European School of Oncology Scientific Updates, Vol. 1, Prognostic and Predictive Value of p53, pp. 321. The Netherlands: Elsevier Science, 1997.
-
Silvestrini R., Benini E., Veneroni S., Daidone M. G., Tomasic G., Squicciarini P., Salvadori B. p53 and bcl-2 expression correlates with clinical outcome in a series of node-positive breast cancer patients. J. Clin. Oncol., 14: 1604-1610, 1996.[Abstract/Free Full Text]
-
Markris A., Powles T. J., Dowsett M., Osborne C. K., Trott P. A., Fernando I. N., Ashley S. E., Ormerod M. G., Titley J. C., Gregory R. K., Allred D. C. Prediction of response to neoadjuvant chemoendocrine therapy in primary breast carcinomas. Clin. Cancer Res., 3: 593-600, 1997.[Abstract]
-
Faille A., Cremoux P., Extra J. M., Linares G., Espie M., Bourstyn E., De Rocquancourt A., Giacchetti S., Marty M., Calvo F. p53 mutations and overexpression in locally advanced breast cancers. Br. J. Cancer, 69: 1145-1150, 1994.[Medline]
-
MacGrogan G., Mauriac L., Durand M., Bonichon F., Trojani M., de Mascarel I., Coindre J. M. Primary chemotherapy in breast invasive carcinoma: predictive value of the immunohistochemical detection of hormonal receptors, p53, c-erbB2, MiB1, pS2 and GST-
. Br. J. Cancer, 74: 1458-1465, 1996.[Medline]
-
Linn S. C., Pinedo H. M., van Ark-Otte J., van der Valk P., Hoekman K., Honkoop A. H., Vermorken J. B., Giaccone G. Expression of drug resistance proteins in breast cancer, in relation to chemotherapy. Int. J. Cancer, 71: 787-795, 1997.[Medline]
-
Dublin E. A., Miles D. W., Rubens R. D., Smith P., Barnes D. M. p53 immunohistochemical staining and survival after adjuvant chemotherapy for breast cancer. Int. J. Cancer, 74: 605-608, 1997.[Medline]
-
Bonetti A., Zaninelli M., Leone R., Cetto G. L., Pelosi G., Biolo S., Menghi A., Manfrin A., Bonetti F., Piubello Q. bcl-2 but not p53 expression is associated with resistance to chemotherapy in advanced breast cancer. Clin. Cancer Res., 4: 2331-2336, 1998.[Abstract]
-
Jansson T., Inganas M., Sjogren S., Norberg T., Lindgren A., Holmberg L., Bergh J. p53 status predicts survival in breast cancer patients treated with or without postoperative radiotherapy: a novel hypothesis based on clinical findings. J. Clin. Oncol., 13: 2745-2751, 1995.[Abstract]
-
Thor A. D., Berry D. A., Budman D. R., Muss H. B., Kute T., Henderson I. C., Barcos M., Cirrincione C., Edgerton S., Allred C., Norton L., Liu E. T. erbB-2, p53, and efficacy of adjuvant therapy in lymph node-positive breast cancer. J. Natl. Cancer Inst., 90: 1346-1360, 1998.[Abstract/Free Full Text]
-
Silvestrini R., Veneroni S., Benini E., Daidone M. G., Luisi A., Leutner M., Maucione A., Kenda R., Zucali R., Veronesi U. Expression of p53, glutathione S-transferase-
, and Bcl-2 proteins and benefit from adjuvant radiotherapy in breast cancer. J. Natl. Cancer Inst., 89: 639-645, 1997.[Abstract/Free Full Text]
-
Lowe S. W., Ruley H. E., Housman D. E. p53-dependent apoptosis modulates the cytotoxicity of anticancer agents. Cell, 74: 957-967, 1993.[Medline]
-
Prives C. How loops, ß sheets, and
helices help us to understand p53. Cell, 78: 543-546, 1994.[Medline]
-
Friend S. A glimpse at the puppet behind the shadow play. Science (Washington DC), 265: 334-335, 1994.[Free Full Text]
-
Borresen A. L., Andersen T. I., Eyford J. E., Cornelis R. S., Thorlacius S., Borg A., Johansson U., Theillet C., Scherneck S., Hartman S. TP53 mutations and breast cancer prognosis: particularly poor survival rates for cases with mutations in the zinc-binding domains. Genes Chromosomes Cancer, 14: 71-75, 1995.[Medline]
-
Berns E. M. J. J., van Staveren I. L., Look M. P., Smid M., Klijn J. G. M., Foekens J. A. Mutations in residues of TP53 that directly contact DNA predict poor outcome in human primary breast cancer. Br. J. Cancer, 77: 1130-1136, 1998.[Medline]
-
Flaman J. M., Frebourg T., Moreau V., Charbonnier F., Martin C., Chappuis P., Sappino A. P., Limacher I. M., Bron L., Benhatter J. A simple p53 functional assay for screening cell lines, blood, and tumors. Proc. Natl. Acad. Sci. USA, 92: 3963-3967, 1995.[Abstract/Free Full Text]
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