PIK3CA and colorectal carcinoma: In these in vitro studies, the HT29 colorectal carcinoma cell line was consistently more sensitive to WX-037 and WX-554 than the HCT116 cell line (26 and 9-fold difference, respectively), which is consistent with other studies where the HT29 cell line exhibited increased sensitivity to pan class I PI3K and/or MEK inhibition, compared to the HCT116 cell line [23, 28, 29].