PDGFA and cancer: Expressions of COL4A2 in tumor cells can establish a migration and invasion‐permissive microenvironment by binding to SDC1‐postive myofibroblasts[37] and induce the transition of PDGFRB‐positive pericytes to cancer associated fibroblasts by secreting platelet‐derived growth factor subunit A (PDGFA) (Figure 6b).[27] These interactions are also supported by the exclusive expression of above ligand‐receptors from epithelial cells‐T cells and epithelial‐fibroblasts (Figure 6c).