Women with many moles are more likely to have breast cancer

Two research reports recently published in PLOS Medicine pointed out that the number of moles (skin pigmented moles) in women may be related to the risk of breast cancer. However, the study did not draw a definite conclusion that an increase in the number of moles on women's skin will increase the risk of breast cancer. In fact, the researchers only explained the possible hormonal and genetic relationship between the two.

"This is not going to be a new worry for women," said Kvaskoff, lead author of one of the studies and affiliated with the National Institutes of Health and Medicine. "I don't think there is a direct causal relationship between having more moles and breast cancer."

Researchers believe that skin moles and breast cancer may be related to the same gene. This means that moles may be able to be used to predict a woman's risk of developing breast cancer. "We are committed to exploring different cancer risk factors," Kvaskoff said. "If more studies show that there is a correlation between moles and breast cancer risk, then the number of moles may become an important risk factor."

In another study, researchers used statistical data from Brigham and Women's Hospital in Boston to investigate the number of moles on the arms and the incidence of breast cancer in 74,523 nurses between 1986 and 2010 to explore the correlation between the two. The results showed that the risk of breast cancer in women without moles was about 8.5%, while the risk in women with more than 15 moles on their left arm was about 11.4%. The research team also found that among menopausal women, those with more than 6 moles had significantly higher levels of estrogen and testosterone in their blood than those without moles.

But it is worth noting that when simply comparing the risk of breast cancer in women with different hormone levels, the correlation between the number of moles and breast cancer disappears.

The results of the Kvaskoff research group showed that among 89,902 female subjects, the incidence of breast cancer in women with multiple moles was 13% higher than that in women without moles between 1990 and 2008. Similar to another study, when the researchers adjusted for other risk factors, including a family history of breast cancer, the association between mole number and risk disappeared.

"The lack of a clear association suggests that moles may not be an important risk factor," Kvaskoff said. In an editorial accompanying the new studies, Fuhrman and Cardenas of Arkansas State University in the United States called for more research in this direction. They wrote, "Future studies should focus on analyzing the relationship between pigmented moles and breast cancer, which will help assess breast cancer risk." Kvaskoff added, "Given the large number of related studies, women with multiple moles should also be promptly checked for skin cancer risk."