COL4A1 and cancer: For example, the stromal subset consisted of endothelial cells identified by expressions of VWF, PECAM1 and KDR, pericytes with high RGS5, ACTA2, and COL4A1 expressions, and cancer-associated fibroblasts (CAFs) identified by significant expressions of COL1A1, DCN and LUM (Figure 1C).