Melatonin helps prevent breast cancer

By David Liu ,PHD

Melatonin (MLT) may help prevent ER+ breast cancer, according to a new study in Breast Cancer Research and Treatment.
Kevin C. Knower and colleagues conducted the in vitro study and found melatonin treatment suppressed transcription of the CYP19A1 gene that encodes the key enzyme aromatase involved in the development of breast cancer.
Aromatase is an enzyme that catalyzes the synthesis of estrogen, a sex hormone that has been found to promote breast cancer. Blocking the enzyme means lowering the estrogen level and slowing down breast cancer cell growth.
The oncostatic properties of melatonin have been demonstrated in laboratory studies which show that melatonin, secreted from the pineal gland, counteracts the effects of estrogen in breast cancer, according to the researchers. And also recent studies of postmenopausal women have determined that the major metabolite of melatonin was significantly associated with lower risk of breast cancer.
In the current study, researchers tested melatonin in normal breast adipose fibroblasts (BAFs), which are the main source of estrogen in breast cancer in postmenopausal women, from women undergoing breast reduction surgery, and breast-caner-associated fobroblasts (CAFs) which were isolated from three women with estrogen receptor (ER) positive invasive breast cancer.
It was found that melatonin at pharmacological, physiological and sub-physiological concentrations suppressed both CYP19A1 transcription and aromatase activity. And the melatonin-induced suppression was mediated through promoter-specific PI.4-, PI.3- and PII-derived CYP19A1 mRNA.
Melatonin at physiological doses could significantly attenuated stimulation of Stimulation of CYP19A1 PII-mRNA and aromatase activity by prostaglandin E2 (PGE2).
The researchers say "Lower levels of MLT in aging women may increase the risk of progressing ER-positive breast cancer through a decreased ability to suppress CYP19A1 expression and subsequent local estrogen production in BAFs/CAFs."

This is not the first study that links melatonin to reduced risk of cancer or death from cancer.
One study released in 2005 in Pineal Research meta-analyzed the protective effect of melatonin, used as a sole treatment or as adjunct treatment, on the death risk from cancer and found that melatonin supplementation reduced risk of death from all solid tumor cancers at one year by 34 percent. The protection was consistent, regardless of the dosage and type of cancer.
Edward Mills of McMaster University in Hamilton, ON, Canada and colleagues conducted the analysis of data from 643 cancer patients who were enrolled in 10 clinical trials.
The researchers commented "The substantial reduction in risk of death, low adverse events reported and low costs related to this intervention suggest great potential for melatonin in treating cancer."
Humans can produce melatonin. But sometimes, people may have melatonin deficiency due to some lifestyle issue. Women who engaged in night shift work were found at high risk for breast cancer probably because they had some difficulty producing sufficient levels of melatonin.
Pauley SM conducted a study and found melatonin levels at night can be reduced by 50 percent when an individual is exposed to a low-level incandescent bulb for as short as 39 minutes.
Melatonin is available as a dietary supplement. In addition to melatonin, vitamin D supplements are more than likely to help prevent or even treat breast cancer.

Source: foodconsumer

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