SLC28A1 and hepatocellular carcinoma: Our RT-PCR results of the expression of the intron retention variant in tumor samples shows an overexpression of hCNT1-IR in human kidney and liver tumor tissues, as well as significant overexpression in human hepatocellular carcinoma (HepG2) cell line compared to normal kidney and liver tissues (Fig. 4 a, b). The overexpression of hCNT1-IR in cancer relative to normal tissues was also demonstrated with pancreatic cancer cells whereby there was a significant downregulation of hCNT in cancer cells (Fig. 4a), but not in hCNT1-IR (Fig. 4b).