Two new studies confirmed that the number of moles on a woman's skin may be a strong indicator of her risk of breast cancer.
Previous studies have highlighted an association between moles and melanoma, the deadliest form of skin cancer. However, not many have focused on how high these risks are. Two new studies conducted recently shed light on this topic, confirming that the number of moles on a woman's skin may be a strong indicator of her risk of breast cancer.
The first study was conducted by researchers from Indiana University and Harvard University. This U.S. study examined 74,523 female nurses. Researchers recorded the number of moles each nurse had. The study subjects were followed for 24 years to see what happened to their health. Researchers found that women with no moles had about an 8 percent chance of developing breast cancer but the women with 15 or more had an 35 percent risk.
Dr. Deanna Attai, a breast surgeon in California, who was not involved in the studies, clarified that the findings don't mean that women with several moles need to panic.
"A cause for alarm in women that have lots of (moles?). No, I don't think so. I would still put more emphasis on obesity and family history," she said, according to a Live Science report.
Moles are scientifically called "nevi." Authors of the study found that women with more moles also have higher levels of hormones.
"Postmenopausal women with six or more nevi had a 45.5 percent higher level of free estradiol and a 47.4 percent higher level of free testosterone compared to those with no nevi," the researchers pointed out in the study published online in PLOS Medicine.
The effect works the other way round too. Older women with higher circulating levels of sex hormones such as estrogen and testosterone were found to have more moles, along with a higher breast cancer risk. Such women also have higher levels of melanocytes, the cells associated with skin cancer and the formation of moles. However, the researchers found that the association wasn't significant after adjusting for known breast cancer risk factors, such as benign breast disease and a family history.
The French study examined 89,000 women ages 40 to 65 during the start of the study. Researchers found that those who reported having "very many" moles at the start of the study were 13 percent more likely to develop breast cancer in the next decade, according to a Daily Mail report.
Findings of both these studies confirm that moles increase the risk of melanoma, which in turn is associated with a higher risk of breast cancer. Researchers also found that women who have many moles and melanoma also have a mutation in the CDKN2A gene. This mutation may be associated with breast cancer.
Authors of both studies also agreed that the associations between moles and breast cancer are really pretty weak and more research is required to confirm this association, according to WebMD.
Moles are relatively common, growing on the skin of most children, and becoming lighter or darker as they age. According to the American Academy of Dermatology, almost every adult has a few moles, with 10 to 40 at various places around the body being fairly common, and normal. Moles are formed naturally by cells in the skin, and the vast majority of moles are completely harmless. But dermatologists say it's a good idea for people to keep an eye on their moles, and report any changes such as sudden growth itching or bleeding.
