GHRHR and cancer: Noteworthy, it has been recently shown that the agonistic GHRH analog MR-409, although promoting tumor cell growth in vitro, exerts antitumor effects in different experimental human cancers in vivo, through the downregulation of pituitary GHRH-R and SV1 in the pituitary gland and tumors, suggesting that, as in the case of the antagonists, the reduction of GHRH-Rs leads to inhibition of tumor growth [50].