Regarding clinical background, we found that pancreatic cancers that were DNA methylation positive and/or KRAS mutation positive in cfDNA were significantly associated with larger sized tumors (36.2 ± 9.0 vs. 45.7 ± 12.6, P = 0.04) and a higher frequency of liver metastasis (20% vs. 53%, P = 0.02), indicating more methylated DNA in circulating blood from advanced pancreatic cancers (S6 Table). Here, KRAS is linked to familial pancreatic carcinoma.