A Qpcr Gene Expression Module Test To Predict Resistance To Cetuximab In Colorectal Cancers Independent Of Kras Mutation Status

e14164 Background: While KRAS mutation predicts resistance to anti-EGFR therapy in colorectal cancer, not all KRAS wild-type patients benefit from such therapy, suggesting that complementary biomarkers capable of identifying additional non-responsive patients would have clinical utility. Methods: To search for such a biomarker, we studied the relationship of cetuximab response with twelve gene expression modules, derived from an unsupervised analysis of 20 independent microarray datasets comprising more than 2,000 colorectal cancer patients. Each module represents a set of highly co-expressed genes related to an important aspect of colorectal cancer variability. Two cetuximab-treated cohorts were studied. The first was a Phase II clinical trial (Khambata-Ford et al, J Clin Oncol, 2007) with accompanying microarray data from pre-treatment biopsies. The second was a single-institution study of cetuximab response from which formalin-fixed paraffin-embedded primary tumor specimens were available. Results: In ...