KRAS and colorectal carcinoma: On the other hand, it seems that KRAS codon 12 mutations, but not codon 13 mutations, are associated with a strong upregulation of vascular endothelial growth factor (VEGF) [24, 25], which is implicated in the promotion of lymphangiogenesis [26], which seems to be related to recurrence and decreased OS after lung metastasectomy in CRC [26].