HSPG2 and neoplasm: Tumoral secreted factors such as leucine, leucine-37 (LL-37) or lysophosphatidic acid (LPA) could recruit MSCs and induce their differentiation in cancer-associated fibroblasts (CAF) through signalling pathways involving Rho kinase, ERK, PLC, and phosphoinositide-3-kinase [19,20].