The only published study of first-line panitumumab plus FOLFIRI in mCRC is a single-arm trial that indicated the efficacy and predictable safety profile of the combination in KRAS WT patients (Köhne et al, 2012), although preliminary data have been presented from a phase II study in which panitumumab plus FOLFOX4 or FOLFIRI was evaluated in patients with KRAS WT colorectal cancer and liver-limited disease (Abad et al, 2014). This evidence concerns the gene KRAS and colorectal cancer.