Because 5-FU is a key therapeutic in the pancreatic-cancer first-line regimen FOLFIRINOX, we chose three pancreatic adenocarcinoma primary cell cultures, PDAC-2, PDAC-5, and LPc167, which express low, intermediate and high TS levels, respectively ( Funel et al., 2008, Firuzi et al., 2019). The gene discussed is TYMS; the disease is familial pancreatic carcinoma.