FGFR2 and cholangiocarcinoma: In our patient MR904, the mutation emerged at progression on pemigatinib, and Varghese and colleagues reported a similar finding at progression on infigratinib in a patient affected by an FGFR2-driven cholangiocarcinoma (one additional patient developed L551F in the context of polyclonal FGFR kinase domain mutations; ref. 21).