GNAS and cholangiocarcinoma: The number of somatic variants detected in patients ranged from 1 to 6: one patient with PDAC had the p.G12D mutation in KRAS gene; three patients (1 with IPMN-derived PDAC, 1 with PDAC, and 1 with IPMN) had 2 clinical tier I–II variants in 2 different genes (KRAS: p.Q61H and GNAS: R201H; KRAS: p.G12D and TP53: p.A88Rfs*6; KRAS: p.G12V and PIK3CA: p.R93W); one patient with CCA presented a total of 6 tier I–II variants in 5 different genes (KRAS: p.G12V, TP53: p.R273C and p.R196*, CDKN2A: p.Y44Lfs*76, BRAF: p.G469A, RNF43: p.W159*).