Further Consideration of the Pigmented Lesion Assay—Reply

In Reply We appreciate the comments by Beatson and Weinstock on our analysis of the pigmented lesion assay (PLA). We agree that it is important to develop tools that have the potential to help decrease biopsies of benign pigmented skin lesions such as the PLA, a gene expression melanoma rule-out test based on obtaining skin samples noninvasively via adhesive patches. We believe that it is important to view the PLA's performance relative to the performance of histopathologic diagnosis. In a large and recent study based on data from 10 US states, the sensitivity of standard histopathologic assessment in comparable in situ and early invasive melanomas was 65% ([Melanocytic Pathology Assessment Tool and Hierarchy for Diagnosis [MPATH-Dx] classes III and IV; 908 + 113 + 11+717 + 928 + 198 = 2875; 2875 of 4416 = 0.65). Even the best dermatopathologist cannot see and describe molecular changes that have yet to develop morphological correlates, thereby highlighting the limitations of our current care standard. Thus, the authors' concerns that the PLA sensitivity is low at 91% should be viewed in this comparative context. In light of this concern, it is also helpful to mention recent follow-up studies that support a PLA sensitivity in real-world settings of 95%.

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