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.