BRAF mutation is associated with DNA methylation in serrated polyps and cancers of the colorectum

Kambara, T., Simms, L. A., Whitehall, V. L. J., Spring, K. J., Wynter, C. V. A., Walsh, M. D., Barker, M. A., Arnold, S., McGivern, A., Matsubara, N., Tanaka, N., Higuchi, T., Young, J., Jass, J. R. and Leggett, B. A. (2004) BRAF mutation is associated with DNA methylation in serrated polyps and cancers of the colorectum. Gut, 53 8: 1137-1144. doi:10.1136/gut.2003.037671

Author Kambara, T.
Simms, L. A.
Whitehall, V. L. J.
Spring, K. J.
Wynter, C. V. A.
Walsh, M. D.
Barker, M. A.
Arnold, S.
McGivern, A.
Matsubara, N.
Tanaka, N.
Higuchi, T.
Young, J.
Jass, J. R.
Leggett, B. A.
Title BRAF mutation is associated with DNA methylation in serrated polyps and cancers of the colorectum
Journal name Gut   Check publisher's open access policy
ISSN 0017-5749
Publication date 2004-08
Sub-type Article (original research)
DOI 10.1136/gut.2003.037671
Volume 53
Issue 8
Start page 1137
End page 1144
Total pages 8
Place of publication United Kingdom
Publisher BMJ Group
Language eng
Subject 11 Medical and Health Sciences
1103 Clinical Sciences
Abstract Mutations in BRAF have been linked with colorectal cancers (CRC) showing high level microsatellite instability (MSI-H). However, the distribution of BRAF mutations in MSI-H cancers remains to be clarified with respect to precursor lesions and the CpG island methylator phenotype (CIMP). METHODS: Forty three hyperplastic polyps (HP), nine mixed polyps (MP), five serrated adenomas (SA), 28 conventional adenomas (AD), 18 hereditary non-polyposis colorectal cancers (HNPCC), and 127 sporadic CRC (46 MSI-H and 81 non-MSI-H) were collected from patients undergoing colectomy for either CRC or hyperplastic polyposis. Twenty five of 57 serrated lesions were derived from four patients with hyperplastic polyposis. HP were further subdivided according to recently documented morphological criteria into 27 classical HP and 16 variant lesions described as "sessile serrated adenoma" (SSA). All tumours were screened for BRAF activating mutations. RESULTS: The BRAF mutation was more frequent in SSA (75%) and MP (89%) than in classical HP (19%), SA (20%), and AD (0%) (p<0.0001), and also in sporadic MSI-H cancers (76%) compared with HNPCC (0%) and sporadic non-MSI-H cancers (9%) (p<0.0001). The BRAF mutation was identified more often in CIMP-high serrated polyps (72%) and CIMP-high CRC (77%) than in CIMP-low (30%) and CIMP-negative (13%) polyps (p = 0.002) as well as CIMP-low (18%) and CIMP-negative (0%) CRC (p<0.0001). CONCLUSIONS: The BRAF mutation was frequently seen in SSA and in sporadic MSI-H CRC, both of which were associated with DNA methylation. Sporadic MSI-H cancers may originate in SSA and not adenomas, and BRAF mutation and DNA methylation are early events in this "serrated" pathway.
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Public Health Publications
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