Melanoma is a type of skin cancer mainly caused by exposure to ultraviolet (UV) light in people with low levels of skin pigment, through the sun's rays or tanning services. Sometimes, the cancer is developed from a mole with changes like irregular edges, an increased size, color change, itchiness or skin breakdown.

Along with family history and a poor immune function, having many moles make a person at greater risk for melanoma.

In a new study presented in New York at the 2015 Summer Academy Meeting of the American Academy of Dermatology, researchers found that while having many moles puts a person at an increased risk for melanoma, having fewer moles will more likely lead to the development of a more aggressive form of melanoma.

"This research reminds us that everyone needs to be alert for melanoma, whether they have many moles or just a few," said Caroline C. Kim, MD, FAAD, board-certified dermatologist, and director of the pigmented lesion clinic and associate director of cutaneous oncology program at Beth Israel Deaconess Medical Center Department of Dermatology at the Harvard Medical School in Boston.

Kim urged the importance of self-examination for signs of skin cancer and the role of board-certified dermatologists in further examining "suspicious spots."

In the study, researchers took a look at data from 281 patients diagnosed with melanoma and who made visits to a Boston hospital from 2013 to 2014. Eighty-nine had 50 or more moles, while 192 had less than 50.

The research team found thicker and more aggressive melanoma in patients with fewer moles. For patients with 50 or more and atypical moles, the researchers found a tendency toward thinner and less aggressive melanoma. Those with more moles were also more likely to be diagnosed with the disease earlier and at a younger age compared with patients who have fewer moles.

According to Kim, patients with fewer moles biologically differ from those with many moles, leading to melanoma variations between the two.

"We already know that melanomas are not at all the same genetically," the board-certified dermatologist said, noting the possibility of different pathways driving melanoma in patients which results in differing degrees of aggressiveness.

"If patients with fewer moles are more prone to aggressive melanoma, then we need to make sure that they are also being educated and screened, in addition to patients with many moles."

Kim also said further studies will definitely be needed to further confirm the findings of the research.

Photo: Scott Robinson | Flickr