For bulk RNA-seq samples, TF enrichment scores were generated using ssGSEA, which calculates normalized difference in empirical cumulative distribution functions of gene expression ranking of genes within or without the gene set of interest.21 While the expression of the POU group (N = 6) was significantly higher in iCCA than HCC (p = 0.012), within iCCA tumors expression of the POU group was highly variable (Figures 4A and 4B; Table S6). Here, TF is linked to hepatocellular carcinoma.