Impact of Genes on Total Number and Type of Nevi


Key Points

  • People who had more nonspecific mole patterns increased their melanoma risk by 2% with every extra mole carried.
  • Certain gene types influenced the number of different nevi types.

A study by Duffy et al in the Journal of Investigative Dermatology reported on specific gene variations affecting the number and types of moles on the body and their role in causing skin cancer. 

“The goal was to investigate the genetic underpinnings of different mole classes, or ‘nevi types,’ and understand how these affect melanoma risk,” said lead study author Rick Sturm, PhD, in a statement. “Based on our work, the number of moles in each category can give a more complete assessment of melanoma risk rather than just the number of moles alone.”

Methods and Findings

A cohort of more than 1,200 patients—half of whom had been diagnosed with melanoma—were recruited into the almost 9-year study. Three key mole classes—reticular, globular, and nonspecific—were magnified under a dermoscope to assess their pattern and risk factors. Their results were then overlayed with genetic testing, which found variations in four major genes.

“We found people who had more nonspecific mole patterns increased their melanoma risk by 2% with every extra mole carried,” explained Dr. Sturm. “As we age, the amount of nonspecific moles on our body [tends to increase] and the risk of developing melanoma increases.”

Dr. Sturm said globular and reticular mole patterns were also found to change over time. “Globular patterns were shown to decrease as we get older, typically petering out after the age of 50 to 60. Reticular moles also decreased over time, but were likely to head down a more dangerous path and develop into the nonspecific pattern.”

“We [also] found some major relationships between genes and the number of moles and patterns when looking at the DNA,” said Dr. Sturm. “Certain gene types influenced the number of different nevi types—for example, the IRF4 gene was found to strongly influence the number of globular nevi found on the body.”

The findings will help dermatologists to better understand mole patterns and provide more holistic care to patients who may be at risk of melanoma.

“For a long time, clinicians have been interested in how pigmented moles relate to melanoma and melanoma risk. With the availability of dermoscopes and imaging, these results provide a new layer of understanding to guide clinical practice,” concluded Dr. Sturm.

Disclosure: For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.