The findings were published online in PLOS Medicine, a top medical journal.
Dr. Han is an epidemiologist and a melanoma (skin cancer) expert. The more moles a person has is a known risk factor for developing melanoma, but this new research indicates a high count of moles may also be a factor in a woman’s risk of developing breast cancer.
“We found that a higher count of moles also indicates higher levels of sex hormones,” Dr. Han said. “Higher levels of hormones have been attributed to increased risk of developing breast cancer. Therefore, it’s possible that the number of moles might be used as a marker for breast cancer risk.”
The researchers used data from 74,523 white, female nurses who participated in the Nurses’ Health Study. Dr. Han used data from the women who had reported the number of nevi less than 3 millimeters in diameter on their left arms from 1986 to 2010.
Dr. Han cautioned that additional studies need to be conducted to study the relationship between cutaneous nevi and breast cancer risk, especially in other populations, as this study focused only on white women.
“There is much yet that we need to investigate to gain a better understanding of this relationship,” Dr. Han said. “We are seeking research funding to support our work because we next want to examine whether the mole count can improve the current breast cancer risk prediction model.”
Other authors of the study included Mingfeng Zhang, Xuehong Zhang and A. Heather Eliassen of Brigham and Women’s Hospital and Harvard Medical School; Abrar A. Qureshi of Brown University; and Susan E. Hankinson of University of Massachusetts.