In a prospective study in advanced pancreatic cancer, ctDNA was analyzed for KRAS mutations using blood samples collected prior to gemcitabine or FOLFIRINOX (5-fluorouracil, oxaliplatin, irinotecan, and leucovorin) treatment and monthly during treatment (median follow-up, 3.7 months). The gene discussed is KRAS; the disease is familial pancreatic carcinoma.