Discouragingly, chronic pancreatitis also shows the KRAS mutation in 10 to 15% of the cases in cfDNA, and to increase the sensitivity and specificity for diagnosis of PC it has additionally been proposed that combining KRAS mutation and serum CA19-9 level can enhance a sensitivity and specificity by 98% and 77%, respectively [306]. The gene discussed is KRAS; the disease is pachyonychia congenita.