MET and prostate neoplasm: The β4 integrin/c-Met interaction can also impinge on other c-Met functions, as demonstrated in endothelial cells, in which HGF induced the formation of a β4 integrin/c-Met/sphingosine 1-phosphate receptor 1 (S1PR1) complex that was localized at CEMs and promoted vascular integrity [80] or in prostate tumour progenitor cells that underwent self-renewal [79].