In addition to patients with cholangiocarcinoma, we saw polyclonal acquired resistance in patients with FGFR2-altered gastroesophageal/gastroesophageal junction cancer and cancer of unknown primary origin, FGFR3-altered non-small cell lung cancer and FGFR1-altered pancreatic cancer. The gene discussed is FGFR1; the disease is cholangiocarcinoma.