KRAS and metastatic malignant neoplasm: Given the reported 25% discordance for KRAS mutation status between primary and metastatic cancers [84], one could expect a significant number of patients with inaccessible brain metastases harboring wild-type KRAS but whose primary solid biopsies showed KRAS mutations, to be excluded from systemic EGFR treatment, disregarding hence the molecular characteristics of their metastatic lesions.