Gene-based test identifies poor-prognosis colon cancers

March 9, 2012 in Cancer

(HealthDay) -- A sensitive and specific gene-based classifier can be used to identify BRAF mutant colon cancer tumors and a subpopulation of BRAF wild-type tumors with poor prognosis, according to a study published March 5 in the Journal of Clinical Oncology.

In an effort to develop a gene expression-based classifier to identify BRAF mutants with high sensitivity, Vlad Popovici, M.D., of the Swiss Institute of Bioinformatics in Lausanne, and colleagues evaluated differential gene expression between BRAF mutant and non-BRAF, non-KRAS mutant cancers from 668 stage II and III colon cancer samples.

The researchers developed a 64 gene-based classifier which identified BRAF mutant tumors with 96 percent sensitivity and 86 percent specificity. A subpopulation of patients who were BRAF wild type (30 percent of KRAS mutants, 13 percent of double wild type) were found to have poor overall survival and poor survival after relapse, similar to that seen in patients with BRAF mutations.

"A characteristic pattern of gene expression is associated with and accurately predicts BRAF mutation status and, in addition, identifies a population of BRAF mutated-like KRAS mutants and double wild-type patients with similarly poor prognosis," the authors write. "This suggests a common biology between these tumors and provides a novel classification tool for cancers, adding prognostic and biologic information that is not captured by the mutation status alone."