HNF4A and colonic neoplasm: Then we used a recombinant adenovirus system to ectopically express HNF4α in a human colon cancer cell line, HCT116, which does not express endogenous HNF4α protein (Supplementary Figure S4); since HNF4α is normally expressed in the colon, this cell line should provide the appropriate environment to examine the effect of HNF4α on endogenous target genes.