Moles and melanomas both form from the same cell called melanocytes. Melanocytes are cells that give colour to the skin to protect it from the sun’s rays. It was thought that specific changes to the DNA sequence of melanocytes, called BRAF gene mutations, are what differentiates moles and melanomas: moles are usually harmless while melanocytes – with mutations in the BRAFV600E gene – are cancerous and often deadly without treatment.

However, research collaborators from the Huntsman Cancer Institute (HCI) and the University of California San Francisco, who studied moles and melanomas donated by patients using transcriptomic profiling (to determine molecular differences between moles and melanomas) and digital holographic cytometry (to track changes in human cells) found something new.

“We discovered a new molecular mechanism that explains how moles form, how melanomas form, and why moles sometimes become melanomas,” said Dr. Robert Judson-Torres, HCI researcher and University of Utah assistant professor of dermatology and oncological sciences.

The researchers found that melanocytes that turn into melanoma are affected by environmental signaling and do not need to have additional mutations. Environmental signalling is when cells receive signals from the environment in the skin around them that give them direction. Melanocytes express genes in different environments, telling them to either divide uncontrollably or stop dividing altogether.

These findings create a foundation for researching potential melanoma biomarkers, allowing doctors to detect cancerous changes in the blood at earlier stages. The researchers are also interested in using the data to better understand potential topical agents to reduce the risk of melanoma, delay development, or stop recurrence, and to detect melanoma early.

“Origins of melanoma being dependent on environmental signals gives a new outlook in prevention and treatment,” said Judson-Torres. “It plays a role in trying to combat melanoma by preventing and targeting genetic mutations. We might also be able to combat melanoma by changing the environment.”