Breast cancer may be predicted by skin moles
Research teams from the U.S. and France have published two new studies that found skin moles may be a predictor of breast cancer. Some studies have shown that women with a greater number of moles are more at risk from hormone-influenced conditions such as endometriosis, leiomyoma and thyroid diseases, but this is the first to look at the association between the number of moles and breast cancer risk.
The researchers analyzed data from the E3N Teachers’ Study Cohort in France, which followed 89,902 women for 18 years. The women were asked to report whether they had no moles, a few moles, many moles, or very many moles. Women who said they had “very many” moles were found to have a 13 percent higher risk of breast cancer than women reporting having no moles.
In the study led by American researchers, the authors observed that moles usually become bigger or darker during pregnancy, which suggests a possible link between moles and hormones.
This team analyzed data from the US Nurses’ Health Study, a cohort of 74,523 female nurses, followed for 24 years. Participants were asked to report the number of moles greater than 3 mm on their left arm. The researchers found that women reporting 15 or more moles were 35 percent more likely to be diagnosed with breast cancer than those reporting no moles. From this, they calculated that women with 15 or more moles had an absolute risk of 11.4 percent of developing breast cancer, compared with an absolute risk of 8.48 percent in women with no moles.
Although both studies found an association between breast cancer and number of moles, neither was able to clearly identify the mechanism that drives the association.