Use of multivariate analysis to suggest a new molecular classification of colorectal cancer
Publication Year 2013-02, Volume 229, Issue #3, Page 441-8
Journal Title
The Journal of Pathology
Publication Type
Journal Article
Molecular classification of colorectal cancer (CRC) is currently based on microsatellite instability (MSI), KRAS or BRAF mutation and, occasionally, chromosomal instability (CIN). Whilst useful, these categories may not fully represent the underlying molecular subgroups. We screened 906 stage II/III CRCs from the VICTOR clinical trial for somatic mutations. Multivariate analyses (logistic regression, clustering, Bayesian networks) identified the primary molecular associations. Positive associations occurred between: CIN and TP53 mutation; MSI and BRAF mutation; and KRAS and PIK3CA mutations. Negative associations occurred between: MSI and CIN; MSI and NRAS mutation; and KRAS mutation, and each of NRAS, TP53 and BRAF mutations. Some complex relationships were elucidated: KRAS and TP53 mutations had both a direct negative association and a weaker, confounding, positive association via TP53-CIN-MSI-BRAF-KRAS. Our results suggested a new molecular classification of CRCs: (1) MSI(+) and/or BRAF-mutant; (2) CIN(+) and/or TP53(-) mutant, with wild-type KRAS and PIK3CA; (3) KRAS- and/or PIK3CA-mutant, CIN(+) , TP53-wild-type; (4) KRAS(-) and/or PIK3CA-mutant, CIN(-) , TP53-wild-type; (5) NRAS-mutant; (6) no mutations; (7) others. As expected, group 1 cancers were mostly proximal and poorly differentiated, usually occurring in women. Unexpectedly, two different types of CIN(+) CRC were found: group 2 cancers were usually distal and occurred in men, whereas group 3 showed neither of these associations but were of higher stage. CIN(+) cancers have conventionally been associated with all three of these variables, because they have been tested en masse. Our classification also showed potentially improved prognostic capabilities, with group 3, and possibly group 1, independently predicting disease-free survival.
colorectal cancer;genetic pathways;clinico-pathological associations;prognostic markers;somatic mutations;molecular classification
WEHI Research Division(s)
Systems Biology And Personalised Medicine
Publisher's Version
Rights Notice
Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.

Creation Date: 2014-02-07 03:29:57
Last Modified: 0001-01-01 12:00:00
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