SLC6A3 and hepatocellular carcinoma: In addition, it was observed that 11/11, 11/11, 4/12, 2/12, 1/11, and 12/12 HCC samples expressed DPYSL4, MMP3, HTRA3, PDX1, C21orf29, and ATHL1 proteins in the cytoplasm/membrane, respectively (Figure 4D), but the IHC staining of PDE6A (0/11), DCAF8L1 (0/11), SLC6A3 (0/11), and RIBC2 (0/10) was negative.