SLC26A3 and colorectal carcinoma: Since SLC26A3 is expressed in colonic epithelium but not in blood cells, detection of circulating tumor cells by identification of SLC26A3 mRNA was suggested as a screening method for CRC, but the specificity has so far been too low for SLC26A3 to qualify as a clinically useful marker (Lauriola et al., 2010).