Given the complexity of resistance mechanisms in patient tumors, which may implicate multiple oncogenes and bypass mechanisms, we modeled the efficacy of our antibodies in the FGFR1-dependent cholangiocarcinoma cell line, CCLP-1, stably transduced to express the FGFR2-PHGDH-WT or FGFR2-PHGDH-V565F alleles (Supplemental Figure 7, C and D). The gene discussed is PHGDH; the disease is cholangiocarcinoma.