SLC22A9 and colorectal cancer: Among the transporters encoded by the SLC22 genes, OAT2 has been detected in colorectal cancer (Tashiro et al., 2014), while to date there are no studies on the expression of the SLC22 genes that encode the OAT2, OAT3, OAT4, and OAT7 proteins, nor on the transporters from the OST/SLC51 family in endometrial and ovarian cancers.