COL4A1 and cancer: Interestingly, UMGs specific to a single cancer type (left of Fig. 2) include a considerable number of genes whose products have similar functions such as COL4A1 and COL1A1 that encode different types of collagen (specific to ESCA), and triplets of genes that encode proteins in the 26S proteasome complex (PSMC1/2/3, specific to UCEC) and mitogen-activated kinases (MAPK1 and MAP2K1/2, specific to THCA).