FGFR2 and cholangiocarcinoma: The elevated expression of FGFR2, CEBPB, but not the other DG genes in CC livers in the subsequent validation could be attributed to the complex genetic etiologies for the cancer prone in CC, in that some DE genes (such as FGFR2 and CEBPB) may have a bigger effect size on most CC patients whereas the other DE genes have effect only in a small group of CC patients.