The aim of this study was to determine the effects of the GHRH-R antagonist MIA-690 in combination with the EGFR inhibitor Gefitinib on different cellular processes, such as viability, adhesion, and cell cycle, involved in cancer progression, using two in vitro experimental models and an androgen-independent prostate cancer cell line, PC-3. This evidence concerns the gene GHRHR and prostate cancer.