Here, we present the results of a prespecified exploratory analysis of the Valentino study (ClinicalTrials.gov identifier: NCT02476045) to investigate the prognostic role of tumor sidedness and PRESSING panel in patients with RAS and BRAF wild-type mCRC who were randomly assigned to maintenance with either single-agent panitumumab or panitumumab plus fluorouracil and leucovorin (FU + LV) after a 4-month induction with panitumumab plus fluorouracil, leucovorin, and oxaliplatin (FOLFOX-4). Here, BRAF is linked to neoplasm.