To the Editor.—
A letter was recently published suggesting an association between breast cancer and malignant melanoma.1 Hormonal factors were suggested by the authors as possibly having a role in explaining this observation. Based on the following studies, depressed pineal gland secretion of melatonin might hypothetically contribute to the development of both malignancies.Cohen et al2 first suggested the role of the pineal gland in the pathogenesis of breast cancer in 1978. It has been shown in experimental animals that decreased levels of melatonin result in increased levels of estrogen and prolactin.3 Receptors to estrogen and other hormones have been found on both breast cancer and melanoma cells.4,5 Pinealectomy in experimental animals results in increased growth of both dimethylbenz(a)anthracene-induced mammary tumors and transplanted melanomas,6,7 and replacement melatonin reverses these adverse effects.6,8 In addition, patients with estrogen-receptor-positive breast cancer and patients with melanoma have decreased
Arbesman H, Byers T. Possible Association Between Breast Cancer and Malignant Melanoma. Arch Dermatol. 1988;124(7):1007. doi:10.1001/archderm.1988.01670070009002
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