Protein markers that can be used to distinguish benign moles from malignant melanoma have been found by US researchers.
These markers could be used to prevent future misdiagnosis of moles and melanoma and to re-evaluate existing diagnoses, the researchers believe.
Diagnosis of melanoma remains problematic in a subset of cases and there is debate about the relative importance that should be assigned to different diagnostic criteria. In addition, many of these criteria overlap with those of atypical, but otherwise benign, lesions.
Patients mistakenly diagnosed with a melanoma live under fear of relapse, while patients mistakenly diagnosed as having a benign mole miss out on appropriate treatment, the researchers pointed out.
Dr Mohammed Kashani-Sabet and colleagues, from the University of California in San Francisco, studied a set of proteins that previously have been found to be expressed at high levels in melanoma.
Differences in protein expression across benign moles and malignant melanomas meant that more than one marker would be needed for a diagnostic test, the researchers found.
Using an algorithm combining five of the proteins allowed them to distinguish benign and malignant growths with an accuracy of more than 90 per cent.
The multimarker test was also able to correct three-quarters of cases in which incorrect diagnoses had been made.
These included melanomas initially misdiagnosed as benign moles, in which the changes in the mole had led to reassessment of biopsies.
'The multimarker assay could be used to assist in the histological diagnosis of melanoma, thereby providing important information to pathologists and other clinicians responsible for caring for patients with melanocytic neoplasms that are difficult to classify,' the researchers said.
'This is important given that mistakes in melanoma diagnosis cause many to undergo inappropriate therapy,' they added.
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