SPINK1 and hepatocellular carcinoma: We first analyzed the expression difference at gene levels between HCC and matched non-cancerous adjacent tissues and identified 1378 differentially expressed genes (DEGs), many of which were identified as differentially expressed in previous studies such as GPC3 (glypican 3) [36], TERT (telomerase reverse transcriptase) [37], SPINK1 (serine peptidase inhibitor, Kazal type 1) [38] and ESM1(endothelial cell-specific molecule 1) [39].