Skip to content

Breast Cancer Health Center

Font Size

Moles May Be Harbinger of Higher Breast Cancer Risk

Studies found that women with more moles on their arms had slightly higher chance of malignancies

WebMD News from HealthDay

By Amy Norton

HealthDay Reporter

TUESDAY, June 10, 2014 (HealthDay News) -- The number of moles a woman has on her skin may hint at her risk of developing breast cancer, new research suggests.

In two separate studies, American and French scientists found that the more moles a woman had, the greater her average risk of breast cancer. In one study, women with 15 or more moles on a single arm were 35 percent more likely to develop breast cancer than women with no moles.

While the connection between moles and breast cancer is not obvious, experts pointed to one plausible explanation: estrogen.

The hormone is known to feed the growth and spread of many breast tumors. And there is also some evidence it influences mole growth; moles tend to get larger and darken during pregnancy, for instance.

"They could be a marker of lifetime exposure to estrogen," said Barbara Fuhrman, an assistant professor at the University of Arkansas for Medical Sciences in Little Rock.

But that's speculation for now. And there could be other underlying reasons for the association -- even some kind of genetic factor, said Fuhrman, who wrote an editorial published June 10 with the studies in the online journal PLOS Medicine.

Her advice to women with numerous moles on their skin: "Don't panic. This is very interesting biologically, but it probably doesn't tell us a lot about an individual woman's risk of breast cancer. It probably tells us more about the general etiology [causes] of breast cancer."

A cancer expert who was not involved in the research agreed. "It's an interesting study. I've never seen this association before," said Dr. Subhakar Mutyala, associate director of the Baylor Scott & White Cancer Institute in Temple, Texas.

However, Mutyala said, "a lot more research" is needed before the findings could be used in routine practice.

There's no proof, he stressed, that women with a lot of moles should start breast cancer screening earlier or have it more often.

"It's not clear how this would fit into current screening recommendations," Mutyala said.

In one of the studies, researchers led by Jiali Han, of the Indiana University Simon Cancer Center in Indianapolis, looked at data on more than 74,000 female nurses in the United States.

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
Breast Cancer Treatments Improving
Resolved To Quit Smoking
Woman getting mammogram
Screening Tests for Women
ovarian cancer overview slideshow
serious woman
what is your cancer risk
10 Ways to Revitalize Slideshow