Introduction
Urological cancers constituting 12% of deaths related to malignancy worldwide are mostly comprised of prostate, bladder, and kidney cancers. The most common type of cancer is the prostate cancer with 300,000 deaths and one million new cases each year1,2. Melatonin is a neuroendocrine hormone that has antioxidant and anticarcinogenic properties and is primarily synthesized by the pineal gland. Apart from the pineal gland, melatonin synthesis is also accomplished through many organs such as the gastrointestinal system, bone marrow, retina, the skin, and lymphocytes3. Melatonin presents exceptional systemic function diversity and has important functions including anti-inflammatory properties, antioxidant and immunomodulation effects, and effects on energy metabolism and hematopoiesis as well as pro-apoptotic, antinociceptive, and antiproliferation activities4. Additionally, cortisol is the resulting product of the hypothalamus-pituitary-adrenal axis, is secreted in a pulsatile manner showing circadian rhythm, and is an important hormone for circadian regulation5,6,7. In a study, it was discovered that the patterns of cortisol secretion may be affected by shift working causing circadian disruption8. It has been discovered that this hormone triggers the risk of cancer through its effects on immune function9,10. For this reason, it is highly likely that the carcinogenicity of circadian disruption affects many areas for both women and men through cortisol levels and melatonin. Long and short -term side effects and risk of cancer may be due to disharmony between the sleep/wake cycle and the endogenous circadian timing system and the disruption of circadian rhythms 11. A hormone, Melatonin, which is secreted by the human pineal gland, has significant anticancer potential in various in vitro and in vivo experimental neoplasia models with chemopreventive, oncostatic, and tumor inhibitory effects4-6. Melatonin is also an effective and powerful endogenous hydroxyl radical scavenger and immunomodulatory agent with the direct and indirect anticancer effects11. Most studies on melatonin in the past thirty years have focused on breast cancer, which is the most common type of cancer observed in women12,13, but there have been few studies conducted on the potential effect of melatonin on prostate cancer14,15. The similarity of the breast and prostate cancer is due to their dependency on sex hormones16,17. In several studies, a correlation was revealed between breast cancer and circadian disruption. However, few studies have examined the correlation between sleep loss or circadian disruption and prostate cancer risk. For this reason, this study evaluated the correlation between melatonin and cortisol levels as the two urinary biomarkers, and examined the effects of circadian regulation hormones on the presence and the stage of prostate cancer and prostate cancer. PSA serum concentration is a marker used in the presence of prostate cancer with the follow-up of patients in order to detect relapse in patients18. We included PSA in the study parameters to study the interaction and correlation between circadian regulation hormones in prostate cancer patients.