The miR31-3p expression level has been associated with progression-free survival in patients with KRAS?wild-type mCRC treated with EGFR?tyrosine kinase inhibitors. In the New EPOC trial, in which patients with mCRC were treated with oxaliplatin- or irinotecan-based chemotherapy or chemotherapy plus cetuximab, correlations between miR31-3p expression and progression-free survival in response to cetuximab were evaluated (Laurent-Puig P, et al. ASCO 2014. Abstract 3523). In patients with high miR31-3p expression, progression-free survival was significantly shorter in the cetuximab arm than in the chemotherapy-alone arm (49.6 weeks vs 64.9 weeks; P = .0177). In patients with low miR31-3p expression, mean progression-free was not significantly different among the 2 arms. Thus, miR31-3p expression is a predictive marker of cetuximab efficacy and may be of value in determining whether to add this agent to a chemotherapy regimen for mCRC.
