PRL and cancer: Apart from the known stress-related hormones (glucocorticoids, prolactin, oxytocin, and dopamine), abnormalities in thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), and growth hormone (GH) have also been found in several cancer types such as colon cancer, gastric cancer, and lung cancer (Kamijo et al., 1987; Mazzoccoli et al., 2010).