OATP1B1 and OATP1B3 deficiency causes human Rotor syndrome by interrupting the reuptake of conjugated bilirubin reuptake into the liver [42]; however, high levels of OATP1B3 transcripts are significantly associated with colorectal cancer and prostate cancer, suggesting that OATP1B3 represents a promising biomarker for those cancers [43, 44]. This evidence concerns the gene SLCO1B1 and colorectal cancer.