ctDNA analysis in three patients with advanced cholangiocarcinoma who disease progressed after treatment with infigratinib, identified multiple mutations on FGFR kinase domain including N549H, N549K, V564F, E565A, K659M, L617V and K641R. Paired tissue analysis detected PI3K/PTEN pathway mutations in some samples (15, 41). The gene discussed is PIK3CG; the disease is cholangiocarcinoma.