POSTN and cancer: It has been shown that due to its tyrosine- and histidine-rich regions, POSTN binds to integrin receptors (αvβ3, αvβ5, α6β4) [39,71] that are present on the surface of cancer cells, thus influencing the regulation of intracellular signaling pathways (PI3K, AKT/PKB) [69,71].