GNRH1 and neoplasm: These receptors can serve as targets for peptide-based drug conjugates due to the fact that receptors for the human hormone peptide gonadotropin-releasing hormone (GnRH) are not only present in pituitary, but also highly expressed on the cell surface of many different tumor types (e.g., breast, ovarian, endometrial, prostate, renal, brain, pancreatic and melanomas), while their presence on healthy tissues is limited [13,14].