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Clinical Investigations |
Imperial Cancer Research Fund Cancer Medicine Research Unit [J. A., M. A. F., K. M., S. H., P. J. S., T. J. P., R. E. B.], Department of Pathology [P. J. C.], Breast Unit [S. D., M. L.], Department of Clinical Oncology [F. C.], Department of Research and Development [V. A.], and Department of Obstetrics and Gynaecology [S. K., J. J. W.], St James’s University Hospital, Leeds LS9 7TF; Imperial Cancer Research Fund Institute of Molecular Medicine Laboratories, University of Oxford, Oxford OX3 9DU [R. B.], United Kingdom
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ABSTRACT |
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 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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INTRODUCTION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Since the pivotal findings in breast cancer of a correlation between tumor angiogenesis, as assessed by microvessel count and density, and metastasis (3) , many studies have confirmed the clinical value of this parameter (4) , and IMD is now established as one of the standard prognostic factors for predicting metastasis and relapse-free or overall survival. Longer-term survival is also predicted by IMD as an independent prognostic factor (5) , and in addition, IMD has been found to add prognostic information to ER status in predicting response to tamoxifen treatment (6) . Higher VEGF mRNA levels have been found in invasive breast carcinoma or DCIS, compared with benign or normal breast tissue (7, 8, 9, 10) , and in association with higher vessel counts (8 , 10, 11, 12, 13) . Assessment of VEGF expression by immunohistochemistry or immunoassay of tissue extracts has shown significant correlations with microvessel counts or density (10 , 14, 15, 16) . In node-negative breast cancer patients, VEGF is a strong independent predictor of relapse-free (17 , 18) and overall (18 , 19) survival.
Clearly, measurement of circulating soluble markers of angiogenesis would be of considerable benefit over more subjective approaches such as immunohistochemical assessments, or immunoassays which involve laborious tissue extraction procedures. Since the original finding of elevated VEGFS concentrations of in patients with cancer (20) , many studies have reported similar findings in patients with breast cancer and many other types of cancer, with higher levels often found in metastatic disease than in localized disease or in progressive disease during treatment (21, 22, 23, 24) . Correlations with prognosis have also been reported for several cancers, e.g., ovarian cancer (25, 26, 27) . However, the interpretation of such studies has been complicated by the demonstration that much of the VEGF measured in serum samples is released from platelets upon activation after venipuncture (28, 29, 30) , with mRNA for VEGF being found in all blood cell types examined, including megakaryocytes, platelets, lymphocytes, CD34+ cells, granulocytes, and monocytes (31, 32, 33, 34) , and VEGF protein being shown to be released by neutrophils (35) and platelets (28, 29, 30 , 33 , 34) after activation in vitro. To measure true basal circulating levels of VEGF, rapidly processed citrated plasma samples are the only suitable material (28) ; they may, therefore, better reflect any circulating VEGF released by the tumor. However, this has yet to be investigated, and the biological significance of platelet- or leukocyte-derived VEGF has yet to be clarified.
This study examined for the first time both VEGFP and VEGFS in blood samples from pre- and postmenopausal healthy controls and patients with benign breast disease, localized breast cancer, breast cancer in remission, or metastatic breast cancer to establish the clinical validity of the different measurements. These results were related to the immunohistochemical expression of VEGF by the tumor, as determined by a new antibody specifically validated for use with paraffin-embedded material (36) , and to the other established clinicopathological prognostic markers, namely MVD, tumor size and grade, lymph node status, and ER and PR status. In particular, the impact of therapy on circulating VEGF concentrations was investigated.
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MATERIALS AND METHODS |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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. Six patients with localized disease, 30 in remission, and 7 with
metastatic disease were receiving tamoxifen at the time of sampling.
Other hormone-based medication included arimidex (one with localized
disease, one in remission, and two with metastatic disease), Megace
(one metastatic), and Danazol (one with localized disease). Two
patients with localized disease, eight in remission, and five with
metastatic disease were receiving chemotherapy. Nine of the 62 patients
with localized disease had DCIS alone; the clinicopathological details
of the remaining 53 patients in this group shown in Table 2
. Patients with metastatic disease included 1 at presentation, 16 at
relapse, and 5 during treatment for relapse. The duration of remission
for the patients in the remission group ranged from <1 to 123 months.
In seven healthy females, changes in circulating VEGF concentrations
during the menstrual cycle were examined with blood samples taken on a
minimum of four occasions during one cycle and concomitant samples
being assayed for circulating estradiol, progesterone, luteinizing
hormone, and follicle-stimulating hormone. The study had been
approved by the local ethics committee, and informed consent was
obtained.
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Measurement of Circulating VEGF.
Plasma and serum samples were analyzed for VEGF using a commercially
available sandwich ELISA obtained from R & D Systems Europe
(Abingdon, United Kingdom). The sensitivity of the assay was 9.0 pg/ml
as quoted by the manufacturer. All samples were assayed in duplicate. A
preliminary evaluation of the assay included the examination of
recovery of recombinant VEGF added to samples, the parallelism
of diluted samples, and the inter- and intra-assay CVs.
Both serum and citrated plasma samples were assayed for VEGF with the
concentration in the citrated plasma sample being corrected for the
dilution effect of the anticoagulant present as a liquid form. Because
our previous study had indicated that the majority of the difference in
VEGF concentrations between serum and plasma samples was accounted for
by release of VEGF from platelets during the clotting process
(28)
, a theoretical platelet-derived VEGF was calculated
and expressed per platelet number, taking into account the hematocrit,
as follows:
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Histopathology and Immunohistochemistry.
Classification of tumors was according to the International Union
against Cancer TNM system (37)
, with grade determined by
the modified Bloom-Richardson criteria according to Elston and Ellis
(38)
. Immunohistochemical staining for CD31, ER, PR, and
VEGF was performed using a standard streptavidin-biotin-peroxidase
detection system with the following primary antibodies (tissue culture
supernatants): for ER, clone 1D5 (DAKO, Cambridge, United Kingdom)
diluted 1:50; for PR, clone PgR 636 (DAKO) diluted 1:50; for CD31,
clone JC/70A (DAKO) diluted 1:30; and for VEGF, clone VG1 (36
, 39)
used undiluted. Tissue sections for ER, PR, and VEGF
immunolabeling were subject to antigen retrieval by immersion in
boiling citrate buffer (pH 6.0) in a microwave three times for 5 min
each, twice for 5 min each, and twice for 5 min each, respectively,
before being either left to cool in the buffer for 20 min (ER and PR)
or cooled on ice for 20 min (VEGF). For CD31 immunolabeling, antigen
retrieval was carried out by immersing sections in boiling citrate
buffer (pH 6.0) for 1 min in a domestic pressure cooker before cooling
in water. A positive control was included in all runs, and for each
case omission of the primary antibody was used as a negative control.
At least 10% of tumor cell nuclei were required to be positive for the tumor to be accepted as ER- or PR-positive, with cytoplasmic staining being disregarded. Staining intensity was variable, and positive staining of adjacent normal parenchymal elements was used as an internal control. VEGF staining was assessed semiquantitatively on a scale from 0 (negative) to 4 (strongly positive). IMD in invasive tumors was assessed after immunostaining for CD31 according to the recent international consensus (40) , using a 25-point Chalkley graticule at x200 magnification (field area, 0.67 mm2). The three most vascular fields, or "hotspots," were initially identified at low power, and the maximum number of points on the graticule was counted for each area. Areas of sclerosis or dense inflammation were avoided. The mean Chalkley counts for the three areas were used in the statistical analysis. For cases of DCIS, "stromal" vascularity was assessed using a Chalkley graticule, and "periductal" vascularity was assessed by a semiquantitative, subjective grading system (40) .
Statistical Analysis.
All statistical analyses were performed using SPSS for Windows (Version
8.0; SPSS, Chicago). The primary analysis was the comparison of the
five patient groups and the circulating VEGF variables. The
Kruskal-Wallis test was used to compare the five groups overall, and
for two-group comparisons we used the Mann-Whitney test. (Corrections
for multiple significance tests were made using the
Bonferroni correction.) For subgroup analyses and to investigate the
relationships between the circulating VEGF variables and other
variables, Spearman’s correlation, 
2,
Kruskal-Wallis, ANOVA, Mann-Whitney, and Student’s t tests
were used as appropriate. P < 0.05 was
considered statistically significant.
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RESULTS |
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Significantly higher VEGF concentrations were found in the serum samples (VEGFS) compared with the corresponding citrated plasma samples (VEGFP; P < 0.0001). When we used the 95th percentile as the cutoff points, the upper limits of normal values for VEGF in the female control group were 62.5 pg/ml plasma for plasma, 590.2 pg/ml for serum, 546.9 pg/ml for the difference between serum and plasma (VEGFdiff), and 1.20 pg/106 platelets; there were no significant differences when compared with a male control group, but the numbers were small (n = 14, data not shown). There were significant differences in age between the groups (P < 0.001), but no significant effects of age or menopausal status were found on VEGF parameters. Analysis of the menstrual cycle data for seven healthy controls showed no definite trend for VEGFS, although within an individual cycle, variation was apparent with most values falling within 25% of the mean cycle value. No cyclical variation was detected in VEGFP because of the low and often undetectable circulating concentrations present.
The circulating VEGF concentrations for each study group are shown in
Fig. 1
. Significant differences between groups were seen in
VEGFP (P < 0.001) and
VEGFS (P = 0.048), but
not in VEGFdiff or platelet VEGF concentrations.
Further analysis revealed that VEGFP
concentrations of patients with localized disease were significantly
elevated compared with normal controls (P = 0.016); patients with metastatic disease had higher levels than normal
controls (P < 0.001), patients with benign
disease (P = 0.009), and patients with
localized disease (P = 0.004). However, the
highest concentrations were seen in patients in remission compared with
normal controls (P < 0.001), patients with
benign disease (P = 0.01), or patients with
localized disease (P = 0.005).
VEGFS concentrations were significantly higher in
patients in remission or those with metastatic disease compared with
normal controls (P = 0.008 and 0.044,
respectively). VEGFdiff was significantly higher
only in the remission group compared with the control group
(P = 0.023).
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= 0.682;
P < 0.001), VEGFdiff
( = 0.601; P < 0.001), and
platelet VEGF concentration ( = 0.530;
P < 0.001). Not surprisingly given the
derivation and the relative proportions, VEGFS
correlated very strongly with VEGFdiff
( = 0.992; P < 0.001), but
in addition, it correlated with platelet VEGF concentration
( = 0.923; P < 0.001). For
the hematological variables, a significant but weak correlation was
found between platelet count and VEGFS
( = 0.172; P = 0.05) and
VEGFdiff ( = 0.204;
P = 0.021), and a negative correlation was
found between VEGFP and hemoglobin ( = -0.227; P = 0.01). When the groups
were examined individually, correlations similar to those above were
found for the VEGF parameters, but no significant correlations were
seen between the VEGF parameters and hematological variables, with the
exception of a significant correlation between white cell count
and VEGFP in patients with metastatic disease
(P < 0.047; = 0.489).
Further analysis of the group of patients in remission revealed a
significant effect of tamoxifen therapy on measured VEGF (Fig. 2
). Significantly higher VEGFP levels were seen in
those patients in remission receiving tamoxifen
(P = 0.004), as were
VEGFS, VEGFdiff, and
platelet VEGF concentrations (P = 0.01,
0.016, and 0.012, respectively). No significant differences were seen
in estradiol levels when subdivided on the basis of tamoxifen therapy.
Multivariate analysis failed to reveal any further influencing
variables. The median time since diagnosis tended to be greater in
patients not receiving tamoxifen (60 months; range, <1–85 months)
compared with those receiving tamoxifen (25 months; range, 2–108
months), but the difference did not reach statistical significance.
Although the numbers of patients were small (14 non-tamoxifen
versus 7 tamoxifen), similar significant effects for
VEGFP (P = 0.004) were
seen in the group of metastatic patients, but the effects on other
measured VEGF parameters failed to reach statistical significance
(P = 0.064, 0.172, and 0.200, respectively).
The plasma and serum VEGF concentrations of patients in remission or
metastatic groups not receiving tamoxifen were not significantly
different from the normal female control group or the patients with
localized breast cancer.
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. Grade and immunohistological variables were unavailable for two
patients because neoadjuvant therapy made assessment unreliable. The
majority of patients had ductal carcinoma of no special type. CD31
immunolabeling gave a highly specific and intense staining of vascular
endothelium both within and outside the areas of tumor. Stromal cells
were negative, and epithelial cytoplasmic positivity was seen in only
one case. Areas of intense inflammation were strongly CD31-positive and
were avoided when selecting areas for assessment. VEGF
immunohistochemical staining was heterogeneous across different tumors
and within tumors, with areas of very intense and very pale staining.
There was staining of normal breast tissue, especially of apocrine
epithelium, but no stromal staining was seen. Labeling of intratumoral
macrophages was also apparent in one case. Two patterns of increased
vascularity were observed in the cases of pure DCIS: stromal and
periductal. All cases demonstrated the former, whereas the
typical "necklace" distribution of the latter was observed in only
one case, which was an unusual case of apocrine DCIS exhibiting the
most intense VEGF positivity of any sample.
In patients with localized invasive cancer, no significant
relationships were found between the circulating VEGF variables and the
recognized immunohistochemical or immunopathological prognostic
indicators examined, with the exception of a significant correlation
between VEGFdiff and ER status ( = 0.325; P = 0.023). Interestingly, an
association between platelets and grade was found ( = -0.359; P = 0.017) and between VEGF
immunostaining and white cell count ( = 0.458;
P = 0.006), with that between VEGF
immunostaining and platelet number just failing to reach statistical
significance (=0.331; P = 0.052). The
relationships between VEGF immunostaining or MVD and other recognized
clinicopathological variables are shown in Table 3
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DISCUSSION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Initially interpreted as reflecting an "overspill" of tumor-derived VEGF into the systemic circulation, VEGFS is now known to be largely platelet-derived (28, 29, 30) . A more accurate basal circulating level, which should reflect normal physiological angiogenesis and any disease-related overspill, should therefore be determined with minimal platelet activation, using citrated plasma (28) . No study has as yet made these comparisons directly, and we report for the first time that VEGFP is a more sensitive measurement than VEGFS in terms of being significantly higher in patients with localized disease compared with controls or patients with benign disease, unlike VEGFS. However, it is also apparent that this measurement would not be an accurate discriminator between the groups because of considerable overlap. The lack of a significant difference in VEGFS between patients with localized breast cancer preoperatively and normal healthy controls confirms previous studies (22 , 24 , 41) . Only two previous studies measured VEGFP in cancer, with concentrations being inversely related to survival and response to chemotherapy in gastrointestinal cancer (42) and with significant differences in patients with prostatic cancer depending on disease state, with a sensitivity of 81% and specificity of 71% for metastatic disease (43) . Because the CVs of immunoassays at the low VEGF concentrations more often found in plasma samples are relatively high, interpretations of changes or differences should take into account their relative magnitude. Although decreases in VEGFS postoperatively (22 , 23) have been described, the extent to which these measurements relate to tumor-derived VEGF is unclear. An alternative explanation may be the contribution of other tumor-derived cytokines, such as interleukin-6 (44) , which is known to induce VEGF expression (45) ; has been shown to correlate with platelet number, VEGFS, and platelet VEGF content (46) ; and thus may conceivably play a role in acting systemically to regulate platelet VEGF content. Changes in VEGFS during chemotherapy coincide with chemotherapy-induced thrombocytopenia and a subsequent rebound increase in platelet number rather than the sustained decrease in VEGFS that would be expected if it was tumor-derived (30) . Similarly, the finding of lower VEGFS in breast cancer patients with disseminated cancer undergoing therapy compared with those untreated (21 , 24) may reflect chemotherapy-induced effects on platelets, effects which may not only be on platelet number but also on platelet volume (47) .
Several studies have now shown that VEGFS correlates with platelet number (30 , 46 , 48) , although significant interindividual variation exists for estimates of platelet VEGF content (28 , 46 , 49) . The platelet VEGF concentration has been reported to be significantly higher in patients with cancer compared with normals, with medians of 1.6 pg/106 platelets (range, 0.3–2.6 pg/106 platelets) and 0.5 pg/106 platelets (0.1–1.6 pg/106 platelets), respectively (49) , but this was not confirmed in the present study, in which we found corresponding medians of 0.47 pg/106 platelets (range, 0.13–1.86 pg/106 platelets) in invasive breast cancer and 0.54 pg/106 platelets (range, 0.08–1.21 pg/106 platelets) in controls. The variability in estimates of platelet-derived VEGF may reflect the use of isolated platelets rather than theoretical derivations from plasma and serum levels, sample sizes, and possible confounding factors such as therapy or the omission of a correction for hematocrit in derived concentrations. For peripheral blood mononuclear cells, median VEGF concentrations of 10.6 pg/106 cells in cancer patients and 0.9 pg/106 cells in normals have been reported (49) , values that clearly make their potential contribution to serum VEGF much smaller than that of platelets given the differential in numbers, but with more marked differences between diseased and normal states. The role of platelets in tumor biology is not clear, but cancer patients frequently have higher platelet counts and an increased platelet consumption compared with healthy individuals; in addition, thrombocytosis is a negative prognostic factor in some cancers, and antitumor effects and improvements in survival have been seen with anticoagulation therapy (50) .
In the all-groups analysis but not in the subgroups, VEGFP was negatively correlated with hemoglobin. A significant negative correlation between VEGFS and hemoglobin has been reported previously in patients with a variety of localized cancers (51) . Such correlations may reflect the disease state, with low hemoglobin often reflecting more advanced disease; alternatively, they may be related to hypoxia-induced VEGF expression, with the decrease in hemoglobin reflecting the hypoxia.
There is no consensus regarding VEGF concentrations during the menstrual cycle; studies have found variable correlations with hormones and have variably reported higher levels of VEGFS in the follicular phase (52) , the luteal phase (53) , the early proliferative (follicular) and secretory (luteal) phases (54) , or no consistent changes (23 , 41) . Interestingly, the patient in our study with the highest circulating VEGF concentrations was receiving Danazol at the time of sampling. Significantly higher levels have been reported in postmenopausal compared with premenopausal women (41 , 52) , which we could not confirm, possibly because of sample sizes.
The inference, after subgroup analysis, that tamoxifen produces significant elevations in circulating VEGF in some patients may have prognostic implications. This was also reflected by an increase in the amount of theoretical platelet-derived VEGF, which indicates that tamoxifen is likely to be acting systemically in terms of its actions on VEGF production. To our knowledge, no previous studies have demonstrated this effect. The antitumor activity of tamoxifen is largely attributed to antiestrogenic properties, although it has mixed agonist/antagonist activity depending on the tissue. However, the effects of tamoxifen are not entirely explained by its action on the ER: some receptor-positive patients fail to respond. Other known potentially therapeutic actions include regulation of circulating concentrations of the breast epithelial mitogen insulin-like growth factor-I and insulin-like growth factor-binding protein I (55 , 56) . Hormonal regulation of VEGF has been demonstrated, with progesterone and progestins such as megestrol acetate stimulating VEGF production by some breast cancer cell lines in vitro (57) and estradiol being shown to stimulate VEGF production in several systems, including endometrial cultures and the uterus in vivo (58, 59, 60, 61) . Tamoxifen itself has been shown to induce VEGF expression in the breast cancer cell line MCF7 by a mechanism that is not thought to be mediated by the ER (62) .
The induction of VEGF by tamoxifen is paradoxical but may be implicated in tamoxifen-associated endometrial hyperplasia, with the endometrium being a possible source of some of the increase in VEGFP seen in this study. Tamoxifen has been shown to increase VEGF expression in uterine tissue (63) and, more recently, to induce production of the novel angiogenic factor adrenomedullin by endometrial macrophages via a nonestrogenic mechanism (64) . In addition, tamoxifen exerts a direct antiproliferative activity on VEGF-stimulated endothelial cell growth, an effect not mediated by the ER (65) . Angiogenesis has been reported to add information to ER status in predicting response to tamoxifen, with the patients having the best prognosis being characterized by low vascularity, ER positivity, few nodes involved, and small low-grade tumors (6) . The determination of the magnitude of the VEGF increase while on tamoxifen may add further prognostic information both with regard to breast cancer and the incidence of endometrial hyperplasia (66) .
In the present study, 80% of tumors were found to be VEGF-positive, which is in agreement with previous reports. However no significant correlation between VEGF staining intensity and Chalkley count was seen, unlike in earlier reports (10 , 14, 15, 16) , although one study found this relationship to be true only for invasive ductal carcinomas or pure DCIS, with VEGF being lower and negatively correlated with angiogenesis in invasive lobular carcinoma (10) . Our findings may reflect the relatively small sample size, the relatively uniform patient populations examined in many earlier studies, antibody specificity, the predominant use of tissue homogenates for assessment of intratumoral VEGF in previous studies, or variability in the techniques used to assess immunohistochemical staining or angiogenesis. This may also reflect differing relative dependencies on other specific angiogenic factors such as thymidine phosphorylase.
IMD has also been reported to correlate with menopausal status, age, and tumor grade (67) , although this is unconfirmed (6) . In the present study, a significant association with tumor size was found that may be expected given the dependence of tumor expansion on angiogenesis, confirming previous reports (67 , 68) . The association of intratumoral VEGF with other clinical prognostic factors is unresolved, with no correlation being found with age, tumor type or size, or hormone receptor status in several studies (14 , 15 , 18) ; however, correlations with tumor size (17 , 19) and grade (19) and an inverse correlation with ER in node-negative breast cancer patients have also been reported (19) . In contrast, we found intratumoral VEGF to be correlated with ER status, which may reflect an estrogenic regulation of VEGF in some patients. Similarly, VEGFdiff was correlated with ER status. Unexpectedly, VEGF was inversely correlated with tumor grade. The prognostic use of intratumoral VEGF assessment is still not clear (15 , 16) , but in node-negative breast cancer, several studies have found VEGF to be a strong independent predictor of relapse-free (17 , 18) and overall (18 , 19) survival. This is being examined prospectively in our study cohort at present. No association between circulating levels of VEGF and intratumoral VEGF assessed immunohistochemically was seen, confirming previous results (69) , although an additional study has reported that the serum-positive rate is associated with MVD and intratumoral VEGF expression when determined by immunoassay (23) .
This study illustrates that VEGFP shows better discrimination than VEGFS in patients with breast cancer and highlights the tamoxifen-associated increase in VEGF concentrations occurring in some patients. The significance of this in relation to disease course or subsequent endometrial pathology, together with the relevance of platelet-tumor cell interactions in tumor angiogenesis and progression, warrants further prospective studies.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Financial support provided by the Imperial
Cancer Research Fund and the Liz Dawn St James’s Hospital Breast
Cancer Appeal. 
2 To whom requests for reprints should be
addressed, at ICRF Cancer Research Unit, St James’s University
Hospital, Leeds LS9 7TF, United Kingdom. Phone: 44 113 2064927; Fax: 44
113 2429886; E-mail: r.banks{at}leeds.ac.uk
3 The abbreviations used are: VEGF, vascular
endothelial growth factor; IMD, intratumoral microvessel density; ER,
estrogen receptor; DCIS, ductal carcinoma in situ;
VEGFS and VEGFP, serum and plasma VEGF; MVD,
microvessel density; PR, progesterone receptor; CV, coefficient of
variation; VEGFdiff, serum minus plasma VEGF.
Received 12/ 6/99. Accepted 4/ 3/00.
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REFERENCES |
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|
|
|
|
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|
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|
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|
|
|
|
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|
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 S. F. Shariat, V. A. Anwuri, D. J. Lamb, N. V. Shah, T. M. Wheeler, and K. M. Slawin Association of Preoperative Plasma Levels of Vascular Endothelial Growth Factor and Soluble Vascular Cell Adhesion Molecule-1 With Lymph Node Status and Biochemical Progression After Radical Prostatectomy J. Clin. Oncol., May 1, 2004; 22(9): 1655 - 1663. [Abstract] [Full Text] [PDF]
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 S. Garvin and C. Dabrosin Tamoxifen Inhibits Secretion of Vascular Endothelial Growth Factor in Breast Cancer in Vivo Cancer Res., December 15, 2003; 63(24): 8742 - 8748. [Abstract] [Full Text] [PDF]
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H. M. W. Verheul and H. M. Pinedo The Importance of Platelet Counts and Their Contents in Cancer Clin. Cancer Res., August 1, 2003; 9(9): 3219 - 3221. [Full Text] [PDF]
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C. E. Murphy, M. R. J. Lansdown, V. Speirs, and P. J. Carder Correspondence re: K. Heer et al., Serum Vascular Endothelial Growth Factor in Breast Cancer: Its Relation with Cancer Type and Estrogen Receptor Status. Clin. Cancer Res., 7: 3491-3494, 2001. Clin. Cancer Res., August 1, 2003; 9(9): 3514 - 3514. [Full Text] [PDF]
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 C. Dabrosin Variability of Vascular Endothelial Growth Factor in Normal Human Breast Tissue in Vivo during the Menstrual Cycle J. Clin. Endocrinol. Metab., June 1, 2003; 88(6): 2695 - 2698. [Abstract] [Full Text] [PDF]
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E. M. J. J. Berns, J. G. M. Klijn, M. P. Look, N. Grebenchtchikov, R. Vossen, H. Peters, A. Geurts-Moespot, H. Portengen, I. L. van Staveren, M. E. Meijer-van Gelder, et al. Combined Vascular Endothelial Growth Factor and TP53 Status Predicts Poor Response to Tamoxifen Therapy in Estrogen Receptor-positive Advanced Breast Cancer Clin. Cancer Res., April 1, 2003; 9(4): 1253 - 1258. [Abstract] [Full Text] [PDF]
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H. F. Dvorak Vascular Permeability Factor/Vascular Endothelial Growth Factor: A Critical Cytokine in Tumor Angiogenesis and a Potential Target for Diagnosis and Therapy J. Clin. Oncol., November 1, 2002; 20(21): 4368 - 4380. [Abstract] [Full Text] [PDF]
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H. Buteau-Lozano, M. Ancelin, B. Lardeux, J. Milanini, and M. Perrot-Applanat Transcriptional Regulation of Vascular Endothelial Growth Factor by Estradiol and Tamoxifen in Breast Cancer Cells: A Complex Interplay between Estrogen Receptors {alpha} and {beta} Cancer Res., September 1, 2002; 62(17): 4977 - 4984. [Abstract] [Full Text] [PDF]
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R. M. Tuttle, M. Fleisher, G. L. Francis, and R. J. Robbins Serum Vascular Endothelial Growth Factor Levels Are Elevated in Metastatic Differentiated Thyroid Cancer but Not Increased by Short-Term TSH Stimulation J. Clin. Endocrinol. Metab., April 1, 2002; 87(4): 1737 - 1742. [Abstract] [Full Text] [PDF]
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M. Colleoni, A. Rocca, M. T. Sandri, L. Zorzino, G. Masci, F. Nole, G. Peruzzotti, C. Robertson, L. Orlando, S. Cinieri, et al. Low-dose oral methotrexate and cyclophosphamide in metastatic breast cancer: antitumor activity and correlation with vascular endothelial growth factor levels Ann. Onc., January 19, 2002; 13(1): 73 - 80. [Abstract] [Full Text] [PDF]
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O. Sezer, C. Jakob, K. Niemoller, R. T.P. Poon, S.-T. Fan, and J. Wong Angiogenesis in Cancer J. Clin. Oncol., July 1, 2001; 19(13): 3299 - 3301. [Full Text]
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J. A. Foekens, H. A. Peters, N. Grebenchtchikov, M. P. Look, M. E. Meijer-van Gelder, A. Geurts-Moespot, T. H. van der Kwast, C. G. J. Sweep, and J. G. M. Klijn High Tumor Levels of Vascular Endothelial Growth Factor Predict Poor Response to Systemic Therapy in Advanced Breast Cancer Cancer Res., July 1, 2001; 61(14): 5407 - 5414. [Abstract] [Full Text] [PDF]
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 W. Jelkmann Pitfalls in the Measurement of Circulating Vascular Endothelial Growth Factor Clin. Chem., April 1, 2001; 47(4): 617 - 623. [Abstract] [Full Text] [PDF]
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N. Takahashi, R. Kawanishi-Tabata, A. Haba, M. Tabata, Y. Haruta, H. Tsai, and B. K. Seon Association of Serum Endoglin with Metastasis in Patients with Colorectal, Breast, and Other Solid Tumors, and SuppressiveEffect of Chemotherapy on the Serum Endoglin Clin. Cancer Res., March 1, 2001; 7(3): 524 - 532. [Abstract] [Full Text]
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 T. Bakheet, M. Frevel, B. R. G. Williams, W. Greer, and K. S. A. Khabar ARED: human AU-rich element-containing mRNA database reveals an unexpectedly diverse functional repertoire of encoded proteins Nucleic Acids Res., January 1, 2001; 29(1): 246 - 254. [Abstract] [Full Text] [PDF]
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