IGF1 and cancer: Newly synthetized GHRH antagonists such as JMR-132, MZ-J-7-118, MZ-5-156, MIA-602 and MIA-690, in addition to their indirect antineoplastic actions through the GHRH-pituitary GH-hepatic insulin-like growth factor-I (IGF-I) axis, were demonstrated to directly inhibit the proliferation of experimental human cancer cell lines in vitro (Figure 1) [1,4,7,8,9].