POSTN and neoplasm: In CRC, tumor cells are closely associated with cancer associated fibroblasts, which secrete different stromal factors, including hepatocyte growth factor, WNT, TGFβ, periostin, prostaglandin E2 (PGE2), bone morphogenetic protein (BMP), and interleukins produced by the tumor microenvironment, which in turn promotes tumor stemness and CIC clonogenicity [13,72,158,159,160].