A genetic factor has been found that prevents moles from becoming melanoma
Copper News from Science Daily: Scientists identify key genetic factor that keeps moles from turning into melanoma
Moles (nevi) are benign tumors on the skin and are present in almost every adult. It has long been known that they grow and can cause skin cancer – melanoma – due to a mutation in the BRAF gene. But until now it was not clear why at some point the moles stop growing. Researchers from the University of Pennsylvania have identified the main genetic factor preventing their further growth and rebirth.
Both nevus cells and melanoma develop from the same skin cells – melanocytes. A mutation in the BRAF gene that stimulates division causes it to be in an "always on" state, constantly provoking division. In moles, cell proliferation usually stops after the accumulation of melanocytes on the surface of the skin reaches a diameter of several millimeters. Scientists were interested in the question of what makes them stop growing with all the activity of BRAF.
In an article published in the journal Cancer Discovery (McNeal et al., CDKN2B loss promotes progression from benign melanocytic nevus to melanoma – VM), it is reported that the BRAF mutation, which stimulates the initial growth of nevi, also stimulates the production of p15 protein, which suppresses tumor growth.
The protein was discovered when researchers compared melanocytes extracted from benign moles with normal skin melanocytes. The main difference was reduced to the concentration of p15: in the nevus cells it was 140 times more.
Ultimately, p15 works as a powerful brake on further cell division, which prevents the nevus from turning into melanoma. "When nevus cells lose this brake in the form of p15, they can begin to divide again and progress into cancer," comments dermatologist Todd W. Ridky, head of the study.
Ridkey and colleagues have developed a new model of human melanoma using cultured tissue containing human nevus cells with the p15 protein removed. In combination with other mutations essential for the development of melanoma and transplantation of tissue samples to mice, the cells deprived of p15 eventually progressed into melanoma in them.
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06.08.2015