SPINK1 and hepatocellular carcinoma: Further analysis of TCGA-LIHC data found SPINK1 expression to be progressively increased from well to poorly differentiated HCC tumors (histological grade/differentiation stages 1 to 4) (Fig. 3e), with high SPINK1 expression clustering well with hepatic progenitor markers (as opposed to its negative correlation with mature hepatocyte markers) (Fig. 3f).