Repercussions of melatonin on the risk of breast cancer: a systematic review and meta-analysis

Abstract

SUMMARY Breast Cancer is common in women, but its etiology is not yet fully understood. Several factors may contribute to its genesis, such as genetics, lifestyle, and the environment. Melatonin may be involved in the process of breast cancer. Therefore, the aim of this study is to evaluate the influence of the levels of melatonin on breast cancer through a systematic review and meta-analysis. We performed a systematic review according to PRISMA recommendations. The primary databases MEDLINE, Embase, and Cochrane were consulted. There was no restriction on the year of publication and language. Data of systematic reviews from April 2017 to September to 2017 were analyzed. The meta-analysis was conducted using RevMan 5.3 software provided by the Cochrane Collaboration. From a total of 570 articles, 9 manuscripts were included in this review. They analy onzed women with breast cancer and control patients, of which 10% and 90% were in the reproductive period and after menopause, respectively. The lowest level of melatonin was found in approximately 55% of studies with breast cancer in post-menopause. The metanalyses of the studies demonstrated low levels of melatonin in breast cancer patients (n=963) compared with control patients (n= 1332), with a mean difference between the studies of −3.54 (CI −6.01, −1.06). Another difference found was in the comparison between smoking patients, with an average difference between 1.80 [0.97-2.63]. Our data suggest that low levels of melatonin might be a risk factor for breast cancer.

How to schedule night shift work in order to reduce health and safety risks

“…Animal studies show that alterations in the light-dark schedule suppress melatonin (3). Furthermore, some prospective cohort studies indicate that women with higher levels of morning urinary melatonin metabolites have a modestly lower risk of breast cancer (16,17).…”

Verification of agomelatine in comparison with melatonin as a therapeutic agent to treat breast cancer

“…The oncostatic and antiproliferative actions of melatonin have been well documented (4,6). By activating MT1 and MT2 receptors, melatonin influences microtubule formation and cytoskeleton organization in ER positive tumor cells, inducing cellular stress that culminates in reduced cell adhesion -one of the factors responsible for cell invasion and migrationcharacteristics of tumor cells (7).…”

“…Currently, several studies have investigated the action of melatonin (N-acetyl-5methoxytryptamine), the main hormone synthesized by the pineal gland, on the breast tumorigenesis (4). Melatonin plays an important role in the circadian cycle, acting as a major regulator of metabolic, physiological, and behavioural activities t, essential for the regulation of hypothalamic-pituitary-gonadal axis independent to the endocrine phenomena (5).…”

The Association of Sleep Disorders, Obesity and Sleep-Related Hypoxia with Cancer

“…Another meta-analysis revealed low concentrations of melatonin in breast cancer patients (n=963) as compared with healthy controls. This finding suggests decreased levels of melatonin may be a risk factor for breast cancer [ 69 ]. Additionally, possible synergistic effects of melatonin combined with chemotherapy have been postulated in non-small-cell-lung cancer [ 65 ], pancreatic cancer [ 68 ], skin cancer [ 70 ], ovarian cancer [ 71 ], colorectal cancer [ 72 ], and other cancers, including breast, hepatic, and prostate cancer [ 73 ].…”