This multicentric study aimed to determine, on paired primary and metastatic tissue samples from a cohort of mCRC patients treated with cetuximab: 1) the nature and density of FcγRIIIA+ (CD16) immune cells, 2) the expression profile of HLA-E/β2m by tumor cells as well as the density of CD94+ immune cells and 3) their impact on both objective response to cetuximab and survival. The gene discussed is KLRD1; the disease is neoplasm.