Here, we report a retrospective exploratory analysis evaluating the prognostic value of the KRAS genotype in MCRC patients enrolled in a previously reported phase II study [4] and in an expanded clinical program proposing FIr-B/FOx intensive regimen as first-line treatment, also verifying recently reported significantly greater effectiveness in L-L compared to other or multiple metastatic (O/MM) patients [6]. Here, KRAS is linked to Miyoshi myopathy.