In the present study, we analyzed the pattern of KRAS discordance (i.e. from WT in primary tumors to MT in related metastatic sites or vice versa); as the sample size was small (N = 25), the KRAS discordance pattern did not show any relation to clinical situations for the development of systemic metastasis (stage IV vs. recurred) or metastatic organs from which tumor specimens were obtained. This evidence concerns the gene KRAS and neoplasm.