KISS1 and cancer: Moreover, KISS1 (encoding Kisspeptin-10) and KISS1R/G-protein-coupled receptor 54 (GPR54) were found to be downregulated in senescent/migration-active HMEC, which is interesting since kisspeptin signaling via its receptor KISS1R/GPR54 has been implicated in the suppression of cell migration [47] and metastasis with a variety of cancers [48] and in the inhibition of human umbilical vein endothelial cell (HUVEC) migration, invasion, and tube formation [49].