Distinguishing features between moles and melanoma

US researchers have developed a method to distinguish between malignant melanomas and atypical moles, or benign naevi.

The assay uses five different markers that are overexpressed in melanoma but were expressed differently in naevi.

Pathologists and dermatologists often have difficulty distinguishing between the two, as they are clinically and microscopically similar.

Atypical moles such as Spitz and dysplastic naevi are thought to be ususally benign, although there is much debate in the literature over this.

The new assay, developed by Mohammed Kashani-Sabet and colleagues from the University of California San Francisco Comprehensive Caner Centre, used the markers ARPC2, FN1, RGS1, SPP1 and WNT2 on the assay.

Based on the differential expression of these proteins, they show their diagnostic achieved a specificity of 95 per cent and a sensitivity of 91 per cent.

They were also able to show that expression was more uniform in melanoma, while benign naevi have an unusual expression pattern, with stronger expression noticed in the outer layer of the mole and lesser at the base.

The work is published in the journal Proceedings of the National Academy of Sciences.

The lead author owns stock in a melanoma diagnostics company.