The interaction between pituitary hormones, GH - PRL, and Growth Factors, GF, plays a fundamental role in the physiological and neoplastic mechanisms of growth, the latter using these factors to a much greater extent compared to the former, with a direct dose-dependent effect on the speed of local or metastatic expansion. In hormone-dependent tumours, the respective male and female sex hormones interact with GH - PRL - GF to sustain the expansion of the tumour. We carried out a review of the literature on the relationship between the expression of GH and GHR in tumour tissues compared to healthy tissues, and on the correlation between this expression and tumour aggressiveness. An over-expression of GH and GHR in tumours was a constant finding. In more than a thousand cases published in various clinical, observational, retrospective studies investigating cervico-facial tumours, lymphoproliferative diseases, breast cancer, prostate cancer, non-small-cell lung cancer, neuroblastomas, oesophageal cancer, glioblastomas, and sarcomas, we constantly found an improvement in objective response, quality of life and survival, compared to conventional oncological protocols, by inhibiting GH and correlated GF using somatostatin.