These suggested that iASPP might mediate p53-independent pathway in PDT process; in other words, as we have demonstrated that the killing effect of PDT on CRC cell might be p53 dependent, we further figure out that iASPP can suppress p53-induced cancer cell apoptosis under PDT treatment through inhibiting p53 expression, thus attenuating the killing effect of PDT on CRC cell. The gene discussed is PPP1R13L; the disease is colorectal carcinoma.