Tracing Nevus Evolution

The genetic evolution from nevus to melanoma has been a source of fascination, and debate, for years. It has long been recognized that BRAF^V600E mutations occur quite frequently and early in acquired nevi. Additional mutational “hits” in nevi have not been reproducibly recovered, despite numerous analyses. To determine the sequence of genetic alterations in melanoma progression, these investigators analyzed 293 cancer-relevant genes in 150 areas of 37 primary melanomas and their adjacent precursor lesions, including lesions that were unequivocally benign, intermediate, and intraepidermal or invasive melanomas.

They found that benign lesions harbored only BRAF^V600E mutations. Other lesions that contained BRAF^V600E and NRAS mutations also harb…