PTPN9 and cholangiocarcinoma: Importantly for cholangiocarcinoma, PTPN9 has been shown to dephosphorylate FGFR2 at the activation loop (pY656/657) and to synergize with the FGFR inhibitor pemigatinib, supporting a role for PTPN9 in modulating FGFR-TKI efficacy [30].