Understanding how cancer produces estrogen within a tumor


iStock_000012934701_Full copyBY JIM HOWE

Picture a flower blooming in a desert, and you have the key to a mystery that puzzled cancer researchers for years.

A common type of breast cancer needs the female hormone estrogen and somehow finds a way to obtain it in the bodies of postmenopausal women, who have low levels of estrogen.

Hironobu Sasano, MD, PhD

Hironobu Sasano, MD, PhD

Just as a desert flower might find a novel way to get water, such as from the air, estrogen-dependent breast cancer can survive in the “hostile environment” of a postmenopausal woman, explains Hironobu Sasano, MD, PhD, a renowned Japanese pathologist. He and other researchers have shown that when little or no estrogen is available in the body, the cancer can produce the hormone within the tumor itself.

This discovery marked Sasano as a “pioneer” in cancer research and intracrinology, a part of endocrinology that studies what takes place within cells, says Upstate pharmacology professor Debashis Ghosh, PhD.

Another way to think of this is to view the cancer as using “homegrown” rather than “imported” estrogen, says Ghosh, who has collaborated on research with Sasano and hosted his recent visit to Upstate to deliver a lecture on breast cancer, estrogen and obesity sponsored by the Carol M. Baldwin Breast Cancer Research Fund of CNY.

In postmenopausal women, the enzyme aromatase can convert the male hormone androgen into estrogen, Sasano says, explaining the promise and limitations of aromatase-inhibitor drugs in blocking this process.

Obesity is involved in the development, recurrence and spread of breast cancer, he says, and reaching and maintaining a healthy body weight means a “significantly better prognosis” for a breast cancer patient, although many other factors come into play.

Sasano, chair of the pathology department at Tohoku University School of Medicine in Sendai, Japan, and president of the Japanese Hormone and Cancer Society, also says that the concepts he outlined could be applied to endometrial cancers, as well as to diseases such as osteoporosis, atherosclerosis and even dementia.

Layout 1This article appears in the winter 2016 issue of Cancer Care magazine.

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