REG4 and cancer: Based on the genes with the largest expression variability, PUC-GBC2 showed an enrichment of genes coding for proteins that form the extracellular matrix, such as COL3A1, POSTN and HAPLN1. On the other hand, genes involved in the regulation of cancer stem cell properties (HNF1A, OLFM4, PCK1 and REG4) and cell metabolism (CYP2B6 and SLC44A4) were overrepresented in PUC-GBC1.