Melanoma-causing mutation can lie dormant in healthy skin

Researchers from The University of Queensland (UQ) and The University of Utah have found that a genetic mutation that causes melanoma can lie dormant in healthy skin. It is believed that their discovery, which has been published in the British Journal of Dermatology, could improve screening of areas more prone to the disease.

The mutation in the BRAF gene was thought to only exist in moles and melanomas, with UQ Frazer Institute PhD candidate Katie Lee saying it was assumed this mutation would almost always cause a mole or melanoma to form. This is because about 50% of melanomas and up to 100% of moles commonly have a mutation in BRAF gene melanocytes — skin cells responsible for pigment production.

Researchers from Queensland’s Dermatology Research Centre team recently examined the mutation in 97 skin samples — most taken from the participants’ backs and shoulders — from a high-risk Australian cohort that appeared normal to both the naked eye and under a microscope. According to Frazer Institute Associate Professor Mitchell Stark, the mutant cells appeared to be dormant, but would likely form a tumour under certain circumstances.

“We have found many examples of the BRAF mutation in normal skin, including skin next to a mole and a melanoma as well as in sun-exposed and sun-protected skin,” Lee said.

“Our research challenges conventional wisdom that BRAF is not generally found in normal skin and that it nearly always causes a melanoma or a mole to form.”

Stark noted that just because a person has this mutation, it doesn’t mean they’ll develop skin cancer, as other external factors are needed for the cells to become malignant. That said, the findings could improve patient screening and melanoma prevention by helping researchers map areas of skin with the mutation and categorising individuals by risk level.

“We noticed our study participants often had all their melanomas and other suspicious lesions removed from the same region of the back,” he said.

“If we can use our findings to show certain areas have more mutations, then we could focus treatment on those spots rather than the whole body.”

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