PIK3CA and colorectal carcinoma: The observed synergism is potentially a TRAIL-specific phenomenon, as in an earlier study, treatment of mutant PIK3CA CRC cells with PI3K inhibitors and cytotoxic drugs such as doxorubicin failed to synergistically increase cell death induction, although proliferation ceased.28 However, re-sensitization of HCT116 PIK3CA-mut cells to TRAIL with any of these inhibitors was not full-blown but only partial.