This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Yuen, S. T. Articles by Leung, S. Y. Search for Related Content PubMed PubMed Citation Articles by Yuen, S. T. Articles by Leung, S. Y.

Similarity of the Phenotypic Patterns Associated with BRAF and KRAS Mutations in Colorectal Neoplasia¹

Departments of Pathology [S. T. Y., T. L. C., W. W. T., A. S. C., S. Y. L.], and Surgery [J. W. H.], University of Hong Kong, Queen Mary Hospital, Hong Kong, and Cancer Genome Project, The Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, United Kingdom [H. D., G. R. B., C. C., P. S., S. E., P. A. F., M. R. S., R. W.]

	ABSTRACT

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 
Activation of the RAS/RAF/extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase pathway by RAS mutations is commonly found in human cancers. Recently, we reported that mutation of BRAF provides an alternative route for activation of this signaling pathway and can be found in melanomas, colorectal cancers, and ovarian tumors. Here we perform an extensive characterization of BRAF mutations in a large series of colorectal tumors in various stages of neoplastic transformation. BRAF mutations were found in 11 of 215 (5.1%) colorectal adenocarcinomas, 3 of 108 (2.8%) sporadic adenomas, 1 of 63 (1.6%) adenomas from familial adenomatous polyposis (FAP) patients, and 1 of 3 (33%) hyperplastic polyps. KRAS mutations were detected in 34% of carcinomas, 31% of sporadic adenomas, 9% of FAP adenomas, and no hyperplastic polyps. Eight of 16 BRAF mutations were V599E, the previously described hotspot, and none of these was associated with a KRAS mutation in the same lesion. The remaining eight mutations involve other conserved amino acids in the kinase domain, and 62.5% have a KRAS mutation in the same tumor. Our data suggest that BRAF mutations are, to some extent, biologically similar to RAS mutations in colorectal cancer because both occur at approximately the same stage of the adenoma-carcinoma sequence, both are associated with villous morphology, and both are less common in adenomas from FAP cases. By contrast, colorectal adenocarcinomas with BRAF mutations are associated with early Dukes’ tumor stages (P = 0.006) and no such relationship was observed for KRAS mutations. The presence in some colorectal neoplasms of mutations in both BRAF and KRAS suggests that modulation of the RAS-RAF-extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase signaling pathway may occur by mutation of multiple components.

	Introduction

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 
Colorectal cancer develops through a multistep process of mutation and clonal expansion. It has been shown that somatic mutation of the RAS genes, in particular KRAS, is an early event in colorectal carcinogenesis, predominantly occurring during the transformation of a small to intermediate sized adenoma (1) .

The RAS proteins participate in the RAS-RAF-MEK-ERK-MAP kinase³ pathway, which mediates cellular responses to growth signals (2) . There are three RAF genes, each encoding cytoplasmic serine/threonine kinases that are regulated by binding to RAS (2 , 3) . We have previously reported that BRAF is somatically mutated in a number of human cancers, including malignant melanoma, colorectal carcinoma, and ovarian borderline (low malignant potential) tumors (4) . Mutations in BRAF occur in two regions of the BRAF kinase domain, the G loop (which mediates binding of ATP) and the activation segment (which protects the substrate binding site). Mutated forms of BRAF that have been studied thus far have elevated kinase activity and can transform NIH3T3 cells (4) .

We now investigate in greater detail the occurrence and spectrum of BRAF mutations in colorectal cancer and in particular their biological relationship to KRAS mutations.

	Materials and Methods

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 
Colorectal Tumor Samples.
Samples from colorectal cancer surgical resections and polyps were collected at Queen Mary Hospital between 1990 and 2001. All specimens were received fresh from the operating theater or endoscopy room. Representative tumor and normal blocks (if available) were snap frozen in liquid nitrogen and stored at -70°C. Frozen sections were cut for histology evaluation. Blocks with tumor occupying >70% of the section area were used. The remainder of each specimen was fixed in 10% buffered formalin and processed through paraffin for histology. DNA was extracted by standard protocols using proteinase K digestion, phenol-chloroform extraction, and ethanol precipitation. The study was approved by the Ethics Committee of the University of Hong Kong.

Mutation Screening.
Screening for mutations was performed as described previously (4) . In brief, we used a capillary-based modified heteroduplex method optimized to run on an ABI PRISM 3100 Genetic Analyzer. PCR primers were designed to amplify the exons plus at least 50 bp of flanking intronic sequence (details of the primers used are available in the supplementary information of our previous paper (4) . Genomic DNA, 12 ng from the test sample, was mixed with 3 ng of control genomic DNA and amplified using standard PCR conditions in which one of the primers was labeled with FAM, NED, or VIC dye. The resulting samples were then analyzed on an ABI PRISM 3100 Genetic Analyser under semidenaturing conditions using optimized separation medium and run conditions. The resulting traces were analyzed using proprietary software to identify samples that produce a shift in peak migration relative to a standard normal control, indicating the presence of a putative sequence variation. Samples that produced a heteroduplex shift were directly sequenced on both strands using the BigDye terminator Cycle Sequencing Ready Reaction Kit (Applied Biosystems) according to the manufacturer’s protocol and analyzed on an ABI PRISM 3100 Genetic Analyser. Analysis of microsatellites for the presence of instability in colorectal cancers was performed as previously described (5) . The following loci were used: BAT26, BAT25, BAT40, TGFßRII (transforming growth factor-ß receptor II), D2S123, D5S346, TP53, D18S58, D3S1067, D5S82, and DCC (deleted in colon cancer). At least five loci were analyzed in each case, including both dinucleotide and mononucleotide loci. Tumors were designated high-level microsatellite instability (MSI-H) when at least 40% loci showed altered electrophoretic mobility relative to the corresponding normal tissue. Tumors with some (but <40%) altered loci were designated low-level microsatellite instability (MSI-L), and those without altered loci were designated microsatellite stable (MSS). For colonic polyps, the MSI status was defined by shifts in BAT26 and BAT25 as corresponding normal tissue was not available.

	Results

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 
We studied 215 colorectal adenocarcinomas from colectomies (212 cases) or local resections of liver metastases (3 cases); 122 were from male and 93 from female patients. The patients’ age ranged from 24 to 89 years (mean age, 58 years). There were 45 tumors in the right colon and 170 in the left colon. There were 28 Dukes’ A, 71 Dukes’ B, 83 Dukes’ C, and 33 Dukes’ D cancers. Nineteen were well-differentiated, 168 were moderately differentiated, and 28 were poorly differentiated. Twenty of these cases have been included in our previous study reporting the incidence of BRAF mutation in various types of human cancer (4) .

We also studied 113 sporadic colorectal polyps; 72 were from male patients, and 41 were from female patients. The patients’ age ranged from 20 to 87 years (mean age, 62 years). There were 66 tubular adenomas, 25 tubulovillous adenomas, 17 villous adenomas, 1 retention polyp, 3 hyperplastic polyps, and 1 Peutz-Jegher polyp. Among these, 4 showed no dysplasia, 32 showed mild dysplasia, 34 showed moderate dysplasia, and 33 showed severe dysplasia. 10 showed early malignant transformation into invasive cancers. 88 were located in the left colon and 24 in the right colon (1 case had unknown tumor location). The size of the polyps ranged from 3 to 45 mm in maximum dimension (mean, 10.88 mm; see Table 6 for size distribution). In addition, 63 polyps from 3 patients with FAP³ were studied. The diagnosis of FAP in these individuals was made on the basis of clinical criteria and confirmed by identification of germline adenomatous polyposis coli mutations (patient 1, deletion exons 4–7; patient 2, c.1349–1355delTCTGTGT; patient 3, c.3284–3285delAG). The FAP polyps ranged from 3 to 20 mm in maximum dimension (mean, 6.3 mm). These tumors were generally small tubular adenomas with low-grade dysplasia (see Table 6 for size distribution); 21 were located in the left colon and 42 were found in the right colon. There were 58 tubular, 1 villous, and 4 tubulovillous adenomas. Forty-two had mild dysplasia, 19 had moderate dysplasia, and 2 had severe dysplasia.

The relationship of BRAF and KRAS mutations with morphology and size of sporadic and FAP adenomas are summarized in Tables 5 and 6 . All three sporadic adenomatous polyps with BRAF mutations showed villous morphology. Although the number of adenomatous polyps with BRAF mutations was small, the association with villous morphology reach borderline statistical significance (P = 0.056, tubular versus villous/tubulovillous, Fisher’s exact test). The trend persisted (P = 0.064) even taking the FAP adenomas into statistical calculation (Table 5) . Overall, a modest association for right-sided location was observed; all 4 adenomas (sporadic and FAP) with BRAF mutation arose in the right colon (from a total of 65) and 0 from the left colon (from a total of 105; P = 0.035, Fisher’s exact test). BRAF mutation was absent in sporadic and FAP adenomas <5 mm in diameter (Table 6) . There was no significant association of BRAF mutation with patient’s age, gender, polyp size, and degree of dysplasia.

Eight of the 16 BRAF mutations were T1796A (resulting in the substitution of valine 599 by glutamate), a previously documented hotspot (4) . None of the colorectal tumors with V599E carried a KRAS mutation. The remaining BRAF mutations were G468E (4) , F594L, and six novel mutations, N580S, D593V, D593G, G595R, T598I, and F467C. The novel mutations all changed highly conserved amino acids (Fig. 1) . Five of eight tumors containing non-V599E BRAF mutations had KRAS mutations. Although one of these, Q22K, is unusual, it has been previously reported and is associated with transforming activity (6) . The incidence of KRAS mutations was significantly higher in colorectal tumors (cancer and polyps) with non-V599E BRAF mutations (five of eight) than in those with V599E mutations (none of 8; P = 0.012, Fisher’s exact test), and also those with no BRAF mutation (102 of 354; P = 0.039, ² test).

View larger version (24K): [in this window] [in a new window]   Fig. 1. Sequence conservation and mutations in the BRAF activation domain (A) and G loop (B) in colorectal tumors analyzed in this report () and total of all published cancers with BRAF mutations () (4) .

	Discussion

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

We observed a lower incidence of BRAF mutations in colorectal cancer than in our previous study of a few cases (4) . The lower incidence is unlikely to be a result of lower sensitivity of the detection methods, given that the same methodology has been used in both studies. Indeed, using this detection method, we found KRAS mutations in 33.7% of cases, an incidence that compared well with our previous series and a compilation of world literature series of KRAS mutations in colorectal cancer (7 , 8) . Moreover, there were no obvious differences in the stage, grade, or histology of the new cases in this report compared with those previously described (4) . Reconciliation of these frequency estimates of BRAF mutations in colorectal cancer will require additional studies.

Our data indicate that BRAF mutations are more common in Dukes’ stage A/B colorectal carcinomas than in Dukes’ stage C/D. This may suggest a less invasive biological behavior for those cancers that harbor BRAF mutations. Follow-up data are available in seven of nine cases with Dukes’ stage B tumors carrying BRAF mutations. They all have survived without recurrence (mean follow-up 60 months, range 5–87) compared with 75% 5-year survival in BRAF-negative Dukes’ B cancers from this series (this comparison does not reach statistical significance). Study of a larger series will be necessary to evaluate further if colorectal cancers with a BRAF mutation are associated with better survival.

We observed many similarities in tumors with BRAF or KRAS mutation that may reflect a common role of the RAS-RAF-extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase pathway in colorectal tumorigenesis. BRAF and KRAS mutations occur at the adenoma stage of the adenoma-carcinoma sequence (although there is a statistically nonsignificant tendency in our series for BRAF mutations to be more common in carcinomas than in adenomas). Like KRAS (9) , BRAF mutations are preferentially more common in villous and rare in tubular adenomas. Also adenomas arising from FAP patients rarely have KRAS (1) or BRAF mutation. Because the FAP adenomas in our series are generally smaller than the sporadic adenomas and most are tubular adenomas, this may partly explain the rarity of KRAS and BRAF mutations. We also found a BRAF mutation in a hyperplastic polyp and a small percentage of these have previously been shown to harbor KRAS mutations (10 , 11) . In contrast, the association of BRAF mutations with Dukes’ stage A/B colorectal cancers was not observed for KRAS mutations.

We previously showed that a mutation in the activation segment, conversion of valine 599 to glutamic acid, is a hotspot for BRAF mutation in human cancer (4) . This mutation results in the insertion of a negatively charged residue adjacent to a site of regulatory phosphorylation at T598, which may mimic regulatory phosphorylation, thus leading to constitutive activation of BRAF independent of RAS. Here we confirmed that V599E is the most common mutation in colorectal tumors, accounting for 50% of mutation observed. Consistent with the proposed autonomous nature of this mutation in the RAS-RAF-MEK-ERK-MAP kinase signaling pathway (4) , mutation of RAS is not required and hence not observed in any of the tumors carrying V599E. We identified six novel BRAF mutations involving other conserved amino acids in the vicinity of the activation segment or glycine-rich loop. Most of these were associated with KRAS mutations in the same cancers. This is consistent with our previous observations on other non-V599 BRAF mutations and suggests modulation of the RAS-RAF-MEK-ERK-MAP kinase signaling pathway by mutation of multiple components in colorectal cancer.

It is interesting to speculate on the functional consequences of three of the novel BRAF mutations, D593V, D593G, and T598I, all located in the kinase activation segment. In BRAF, both T598 and S601 require phosphorylation to achieve maximal kinase activity. Phosphorylation of these two residues occurs after recruitment of BRAF to the membrane by activated RAS. In experimental systems, replacement of these two residues by acidic amino acids can mimic regulatory phosphorylation and results in RAS-independent BRAF activation. However, replacement by nonpolar amino acids results in complete abrogation of BRAF kinase activity (12) . Similarly, previously described experimental mutants of BRAF D593 abolish kinase activity. Although all of the cancer-associated BRAF mutants previously studied were associated with increased kinase activity and transforming activity in NIH3T3 cells (4) , the current results suggest that some BRAF mutations found in human cancer may reduce or abolish kinase and transforming activities. Clearly, more studies are required to functionally characterize these mutants.

	Note Added in Proof

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 
While this paper was being considered for publication, a similar study was published by Rajagopalan et al., Nature, 418: 934, 2002.

	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 This work was supported by the Wellcome Trust, the Institute of Cancer Research, the Research Grants Council of the Hong Kong Special Administrative Region (HKU 7330/00M), the Hong Kong Society of Gastroenterology, and the Hong Kong Cancer Fund.

² To whom requests for reprints should be addressed, at Department of Pathology, University of Hong Kong, Queen Mary Hospital, Hong Kong. Phone: 852 28554401; Fax: 852 28725197; E-mail: suetyi{at}hkucc.hk (S. Y. L.); or Cancer Genome Project, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1SA, United Kingdom. Phone: 01223 494951; Fax: 01223 494969; E-mail: mrs{at}sanger.ac.uk (M. R. S.).

³ The abbreviations used are: RAS-RAF-ERK-MEK-MAP kinase, RAS-RAF-extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase; FAP, familial adenomatous polyposis; MSI, microsatellite instability.

Received 8/ 2/02. Accepted 9/24/02.

	REFERENCES

Top ABSTRACT Introduction Materials and Methods Results Discussion Note Added in Proof REFERENCES

 

1. Vogelstein B., Fearon E. R., Hamilton S. R., Kern S. E., Preisinger A. C., Leppert M., Nakamura Y., White R., Smits A. M., Bos J. L. Genetic alterations during colorectal-tumor development. N. Engl. J. Med., 319: 525-532, 1988.[Abstract]
2. Peyssonnaux C., Eychene A. The Raf/MEK/ERK pathway: new concepts of activation. Biol. Cell, 93: 53-62, 2001.[Medline]
3. Kolch W. Meaningful relationships: the regulation of the Ras/Raf/MEK/ERK pathway by protein interactions. Biochem. J., 351 (Pt. 2): 289-305, 2000.
4. Davies H., Bignell G. R., Cox C., Stephens P., Edkins S., Clegg S., Teague J., Woffendin H., Garnett M. J., Bottomley W., Davis N., Dicks E., Ewing R., Floyd Y., Gray K., Hall S., Hawes R., Hughes J., Kosmidou V., Menzies A., Mould C., Parker A., Stevens C., Watt S., Hooper S., Wilson R., Jayatilake H., Gusterson B. A., Cooper C., Shipley J., Hargrave D., Pritchard-Jones K., Maitland N., Chenevix-Trench G., Riggins G. J., Bigner D. D., Palmieri G., Cossu A., Flanagan A., Nicholson A., Ho J. W., Leung S. Y., Yuen S. T., Weber B. L., Seigler H. F., Darrow T. L., Paterson H., Marais R., Marshall C. J., Wooster R., Stratton M. R., Futreal P. A. Mutations of the BRAF gene in human cancer. Nature (Lond.), 417: 949-954, 2002.[Medline]
5. Chan T. L., Yuen S. T., Chung L. P., Ho J. W., Kwan K. Y., Chan A. S., Ho J. C., Leung S. Y., Wyllie A. H. Frequent microsatellite instability and mismatch repair gene mutations in young Chinese patients with colorectal cancer. J. Natl. Cancer Inst., 91: 1221-1226, 1999.[Abstract/Free Full Text]
6. Tsukuda K., Tanino M., Soga H., Shimizu N., Shimizu K. A novel activating mutation of the K-ras gene in human primary colon adenocarcinoma. Biochem. Biophys. Res. Commun., 278: 653-658, 2000.[Medline]
7. Yuen S. T., Chung L. P., Leung S. Y., Luk I. S., Chan S. Y., Ho J. C., Ho J. W., Wyllie A. H. Colorectal carcinoma in Hong Kong: epidemiology and genetic mutations. Br. J. Cancer, 76: 1610-1616, 1997.[Medline]
8. Andreyev H. J., Norman A. R., Cunningham D., Oates J., Dix B. R., Iacopetta B. J., Young J., Walsh T., Ward R., Hawkins N., Beranek M., Jandik P., Benamouzig R., Jullian E., Laurent-Puig P., Olschwang S., Muller O., Hoffmann I., Rabes H. M., Zietz C., Troungos C., Valavanis C., Yuen S. T., Ho J. W., Croke C. T., O’Donoghue D. P., Giaretti W., Rapallo A., Russo A., Bazan V., Tanaka M., Omura K., Azuma T., Ohkusa T., Fujimori T., Ono Y., Pauly M., Faber C., Glaesener R., de Goeij A. F., Arends J. W., Andersen S. N., Lovig T., Breivik J., Gaudernack G., Clausen O. P., De Angelis P. D., Meling G. I., Rognum T. O., Smith R., Goh H. S., Font A., Rosell R., Sun X. F., Zhang H., Benhattar J., Losi L., Lee J. Q., Wang S. T., Clarke P. A., Bell S., Quirke P., Bubb V. J., Piris J., Cruickshank N. R., Morton D., Fox J. C., Al Mulla F., Lees N., Hall C. N., Snary D., Wilkinson K., Dillon D., Costa J., Pricolo V. E., Finkelstein S. D., Thebo J. S., Senagore A. J., Halter S. A., Wadler S., Malik S., Krtolica K., Urosevic N. Kirsten ras mutations in patients with colorectal cancer: the "RASCAL II" study. Br. J. Cancer, 85: 692-696, 2001.[Medline]
9. Maltzman T., Knoll K., Martinez M. E., Byers T., Stevens B. R., Marshall J. R., Reid M. E., Einspahr J., Hart N., Bhattacharyya A. K., Kramer C. B., Sampliner R., Alberts D. S., Ahnen D. J. Ki-ras proto-oncogene mutations in sporadic colorectal adenomas: relationship to histologic and clinical characteristics. Gastroenterology, 121: 302-309, 2001.[Medline]
10. Rashid A., Houlihan P. S., Booker S., Petersen G. M., Giardiello F. M., Hamilton S. R. Phenotypic and molecular characteristics of hyperplastic polyposis. Gastroenterology, 119: 323-332, 2000.[Medline]
11. Otori K., Oda Y., Sugiyama K., Hasebe T., Mukai K., Fujii T., Tajiri H., Yoshida S., Fukushima S., Esumi H. High frequency of K-ras mutations in human colorectal hyperplastic polyps. Gut, 40: 660-663, 1997.[Abstract/Free Full Text]
12. Zhang B. H., Guan K. L. Activation of B-Raf kinase requires phosphorylation of the conserved residues Thr598 and Ser601. EMBO J., 19: 5429-5439, 2000.[Medline]

This article has been cited by other articles:

				J J Y Sung, J Y W Lau, G P Young, Y Sano, H M Chiu, J S Byeon, K G Yeoh, K L Goh, J Sollano, R Rerknimitr, et al. Asia Pacific consensus recommendations for colorectal cancer screening Gut, August 1, 2008; 57(8): 1166 - 1176. [Abstract] [Full Text] [PDF]

				D. R. English, J. P. Young, J. A. Simpson, M. A. Jenkins, M. C. Southey, M. D. Walsh, D. D. Buchanan, M. A. Barker, A. M. Haydon, S. G. Royce, et al. Ethnicity and Risk for Colorectal Cancers Showing Somatic BRAF V600E Mutation or CpG Island Methylator Phenotype Cancer Epidemiol. Biomarkers Prev., July 1, 2008; 17(7): 1774 - 1780. [Abstract] [Full Text] [PDF]

				O. N. Ikediobi, M. Reimers, S. Durinck, P. E. Blower, A. P. Futreal, M. R. Stratton, and J. N. Weinstein In vitro differential sensitivity of melanomas to phenothiazines is based on the presence of codon 600 BRAF mutation Mol. Cancer Ther., June 1, 2008; 7(6): 1337 - 1346. [Abstract] [Full Text] [PDF]

				Y. Suehiro, C. W. Wong, L. R. Chirieac, Y. Kondo, L. Shen, C. R. Webb, Y. W. Chan, A. S.Y. Chan, T. L. Chan, T.-T. Wu, et al. Epigenetic-Genetic Interactions in the APC/WNT, RAS/RAF, and P53 Pathways in Colorectal Carcinoma Clin. Cancer Res., May 1, 2008; 14(9): 2560 - 2569. [Abstract] [Full Text] [PDF]

				A. Sanchez-de-Abajo, M. de la Hoya, M. van Puijenbroek, A. Tosar, J.A. Lopez-Asenjo, E. Diaz-Rubio, H. Morreau, and T. Caldes Molecular Analysis of Colorectal Cancer Tumors from Patients with Mismatch Repair Proficient Hereditary Nonpolyposis Colorectal Cancer Suggests Novel Carcinogenic Pathways Clin. Cancer Res., October 1, 2007; 13(19): 5729 - 5735. [Abstract] [Full Text] [PDF]

				C. Spittle, M. R. Ward, K. L. Nathanson, P. A. Gimotty, E. Rappaport, M. S. Brose, A. Medina, R. Letrero, M. Herlyn, and R. H. Edwards Application of a BRAF Pyrosequencing Assay for Mutation Detection and Copy Number Analysis in Malignant Melanoma J. Mol. Diagn., September 1, 2007; 9(4): 464 - 471. [Abstract] [Full Text] [PDF]

				B. R. Davies, A. Logie, J. S. McKay, P. Martin, S. Steele, R. Jenkins, M. Cockerill, S. Cartlidge, and P. D. Smith AZD6244 (ARRY-142886), a potent inhibitor of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 kinases: mechanism of action in vivo, pharmacokinetic/pharmacodynamic relationship, and potential for combination in preclinical models Mol. Cancer Ther., August 1, 2007; 6(8): 2209 - 2219. [Abstract] [Full Text] [PDF]

				H. Hao, V. M. Muniz-Medina, H. Mehta, N. E. Thomas, V. Khazak, C. J. Der, and J. M. Shields Context-dependent roles of mutant B-Raf signaling in melanoma and colorectal carcinoma cell growth Mol. Cancer Ther., August 1, 2007; 6(8): 2220 - 2229. [Abstract] [Full Text] [PDF]

				J. Vandrovcova, K. Lagerstedt-Robinsson, L. Pahlman, and A. Lindblom Somatic BRAF-V600E Mutations in Familial Colorectal Cancer. Cancer Epidemiol. Biomarkers Prev., November 1, 2006; 15(11): 2270 - 2273. [Abstract] [Full Text] [PDF]

				C. H.F. Chan, D. Cook, and C. P. Stanners Increased colon tumor susceptibility in azoxymethane treated CEABAC transgenic mice Carcinogenesis, September 1, 2006; 27(9): 1909 - 1916. [Abstract] [Full Text] [PDF]

				M. R. James, T. Dumeni, M. S. Stark, D. L. Duffy, G. W. Montgomery, N. G. Martin, and N. K. Hayward Rapid Screening of 4000 Individuals for Germ-line Variations in the BRAF Gene Clin. Chem., September 1, 2006; 52(9): 1675 - 1678. [Abstract] [Full Text] [PDF]

				I.-J. Kim, H. C. Kang, S.-G. Jang, K. Kim, S.-A Ahn, H.-J. Yoon, S. N. Yoon, and J.-G. Park Oligonucleotide microarray analysis of distinct gene expression patterns in colorectal cancer tissues harboring BRAF and K-ras mutations Carcinogenesis, March 1, 2006; 27(3): 392 - 404. [Abstract] [Full Text] [PDF]

				D. J. Panka, W. Wang, M. B. Atkins, and J. W. Mier The Raf Inhibitor BAY 43-9006 (Sorafenib) Induces Caspase-Independent Apoptosis in Melanoma Cells Cancer Res., February 1, 2006; 66(3): 1611 - 1619. [Abstract] [Full Text] [PDF]

				K. Mercer, S. Giblett, S. Green, D. Lloyd, S. DaRocha Dias, M. Plumb, R. Marais, and C. Pritchard Expression of Endogenous Oncogenic V600EB-raf Induces Proliferation and Developmental Defects in Mice and Transformation of Primary Fibroblasts Cancer Res., December 15, 2005; 65(24): 11493 - 11500. [Abstract] [Full Text] [PDF]

				M. Beeram, A. Patnaik, and E. K. Rowinsky Raf: A Strategic Target for Therapeutic Development Against Cancer J. Clin. Oncol., September 20, 2005; 23(27): 6771 - 6790. [Abstract] [Full Text] [PDF]

				W. L. Ince, A. M. Jubb, S. N. Holden, E. B. Holmgren, P. Tobin, M. Sridhar, H. I. Hurwitz, F. Kabbinavar, W. F. Novotny, K. J. Hillan, et al. Association of k-ras, b-raf, and p53 Status With the Treatment Effect of Bevacizumab J Natl Cancer Inst, July 6, 2005; 97(13): 981 - 989. [Abstract] [Full Text] [PDF]

				K. Krohn, D. Fuhrer, Y. Bayer, M. Eszlinger, V. Brauer, S. Neumann, and R. Paschke Molecular Pathogenesis of Euthyroid and Toxic Multinodular Goiter Endocr. Rev., June 1, 2005; 26(4): 504 - 524. [Abstract] [Full Text] [PDF]

				E. C. Seales, G. A. Jurado, B. A. Brunson, J. K. Wakefield, A. R. Frost, and S. L. Bellis Hypersialylation of {beta}1 Integrins, Observed in Colon Adenocarcinoma, May Contribute to Cancer Progression by Up-regulating Cell Motility Cancer Res., June 1, 2005; 65(11): 4645 - 4652. [Abstract] [Full Text] [PDF]

				C W Wong, Y S Fan, T L Chan, A S W Chan, L C Ho, T K F Ma, the Cancer Genome Project, S T Yuen, and S Y Leung BRAF and NRAS mutations are uncommon in melanomas arising in diverse internal organs J. Clin. Pathol., June 1, 2005; 58(6): 640 - 644. [Abstract] [Full Text] [PDF]

				K Busby and A Morris Detection of BRAF mutations in colorectal tumours and peritoneal washings using a mismatch ligation assay J. Clin. Pathol., April 1, 2005; 58(4): 372 - 375. [Abstract] [Full Text] [PDF]

				R. Beach, A. O.-O. Chan, T.-T. Wu, J. A. White, J. S. Morris, S. Lunagomez, R. R. Broaddus, J.-P. J. Issa, S. R. Hamilton, and A. Rashid BRAF Mutations in Aberrant Crypt Foci and Hyperplastic Polyposis Am. J. Pathol., April 1, 2005; 166(4): 1069 - 1075. [Abstract] [Full Text] [PDF]

				M. Eszlinger, K. Krohn, K. Berger, J. Lauter, S. Kropf, M. Beck, D. Fuhrer, and R. Paschke Gene Expression Analysis Reveals Evidence for Increased Expression of Cell Cycle-Associated Genes and Gq-Protein-Protein Kinase C Signaling in Cold Thyroid Nodules J. Clin. Endocrinol. Metab., February 1, 2005; 90(2): 1163 - 1170. [Abstract] [Full Text] [PDF]

				P. Smyth, S. Finn, S. Cahill, E. O'Regan, R. Flavin, J. J. O'Leary, and O. Sheils ret/PTC and BRAF Act as Distinct Molecular, Time-Dependant Triggers in a Sporadic Irish Cohort of Papillary Thyroid Carcinoma International Journal of Surgical Pathology, January 1, 2005; 13(1): 1 - 8. [Abstract] [PDF]

				T. Nagasaka, H. Sasamoto, K. Notohara, H. M. Cullings, M. Takeda, K. Kimura, T. Kambara, D. G. MacPhee, J. Young, B. A. Leggett, et al. Colorectal Cancer With Mutation in BRAF, KRAS, and Wild-Type With Respect to Both Oncogenes Showing Different Patterns of DNA Methylation J. Clin. Oncol., November 15, 2004; 22(22): 4584 - 4594. [Abstract] [Full Text] [PDF]

				C. Oliveira, J. L. Westra, D. Arango, M. Ollikainen, E. Domingo, A. Ferreira, S. Velho, R. Niessen, K. Lagerstedt, P. Alhopuro, et al. Distinct patterns of KRAS mutations in colorectal carcinomas according to germline mismatch repair defects and hMLH1 methylation status Hum. Mol. Genet., October 1, 2004; 13(19): 2303 - 2311. [Abstract] [Full Text] [PDF]

				T Kambara, L A Simms, V L J Whitehall, K J Spring, C V A Wynter, M D Walsh, M A Barker, S Arnold, A McGivern, N Matsubara, et al. BRAF mutation is associated with DNA methylation in serrated polyps and cancers of the colorectum Gut, August 1, 2004; 53(8): 1137 - 1144. [Abstract] [Full Text] [PDF]

				T. Ikenoue, Y. Hikiba, F. Kanai, J. Aragaki, Y. Tanaka, J. Imamura, T. Imamura, M. Ohta, H. Ijichi, K. Tateishi, et al. Different Effects of Point Mutations within the B-Raf Glycine-Rich Loop in Colorectal Tumors on Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase Kinase/Extracellular Signal-Regulated Kinase and Nuclear Factor {kappa}B Pathway and Cellular Transformation Cancer Res., May 15, 2004; 64(10): 3428 - 3435. [Abstract] [Full Text] [PDF]

				K. Konishi, T. Yamochi, R. Makino, K. Kaneko, T. Yamamoto, H. Nozawa, A. Katagiri, H. Ito, K. Nakayama, H. Ota, et al. Molecular Differences between Sporadic Serrated and Conventional Colorectal Adenomas Clin. Cancer Res., May 1, 2004; 10(9): 3082 - 3090. [Abstract] [Full Text] [PDF]

				K. Fransen, M. Klintenas, A. Osterstrom, J. Dimberg, H.-J. Monstein, and P. Soderkvist Mutation analysis of the BRAF, ARAF and RAF-1 genes in human colorectal adenocarcinomas Carcinogenesis, April 1, 2004; 25(4): 527 - 533. [Abstract] [Full Text] [PDF]

				M. Shinozaki, A. Fujimoto, D. L. Morton, and D. S. B. Hoon Incidence of BRAF Oncogene Mutation and Clinical Relevance for Primary Cutaneous Melanomas Clin. Cancer Res., March 1, 2004; 10(5): 1753 - 1757. [Abstract] [Full Text] [PDF]

M. Casula, M. Colombino, M. P. Satta, A. Cossu, P. A. Ascierto, G. Bianchi-Scarra, D. Castiglia, M. Budroni, C. Rozzo, A. Manca, et al. BRAF Gene Is Somatically Mutated but Does Not Make a Major Contribution to Malignant Melanoma Susceptibility: The Italian Melanoma Intergroup Study J. Clin. Oncol., January 15, 2004; 22(2): 286 - 292. [Abstract] [Full Text] [PDF]