Over-Expression of GH/GHR in Breast Cancer and Oncosuppressor Role of Somatostatin as a Physiological Inhibitor

Abstract

Background: The interaction between pituitary hormones (Growth Hormone-Prolactin), ovarian hormones (Estradiol) and growth factors forms the basis of the mechanisms underlying the growth of tumors of the breast. The literature contains reports of the increased expression of the mitogenic GH (Growth Hormone)/IGF1 (Insulin-Like Growth Factor) axis in tumor tissues compared to healthy tissues, with a directly proportional dose-dependent relationship between GH/IGF1, proliferative index and invasive ability in numerous types of tumors. Methods and Findings: We carried out this experimental research on the mitogenic role of GH and consequently on the rationale of the anticancer use of its inhibition. The levels of expression of several genes, GH and GHR, were evaluated in 39 cases of breast cancer, divided according to different risk levels on the basis of immunohistochemical and histological tests with nuclear grade. Conclusion: Research showed that breast cancers with a high and intermediate risk of recurrence are characterized by over-expression of GH and of its receptor (GHR). The expression was limited in cases with a low risk. The overexpression of GH-GHR in breast cancer with a ratio proportional to the level of aggressiveness is a rationale that can encourage a therapeutic intervention with inhibition of the mitogenic GH-IGF1-PRL axis and estrogen.