TP53 and colonic neoplasm: Although OATP1B3 influx mechanisms are still unknown in colon cancer, there is sufficient evidence suggesting that OATP1B3 is overexpressed in a large proportion of colon tumors, and that this overexpression contributes to cell survival in the presence of oxalaplatin and camptothecin; the latter effect may be related to p53 expression [2].