KRAS and pancreatic adenocarcinoma: We used these two pancreatic adenocarcinoma cell lines because they carry constitutively activated endogenous K-RAS mutations (K-RASG12C and K-RASG12D respectively) and in an initial pre-screen of a panel of pancreatic cancer cell lines, we observed low expression of TSPAN6 in these lines compared to others examined (data not shown).