Concordance of Preferentially Expressed Antigen in Melanoma by Non-Invasively Collected Polymerase Chain Reaction and Immunohistochemistry on Paraffin Embedded Tissue

Background: ​
 Pigmented lesion evaluation remains a challenging aspect of dermatology. The DermTech Melanoma Test (DMT) is non-invasive gene-expression test designed to rule-out melanoma. It consists the pigmented assay, which detects RNA products Long Intergenic Non-Coding 00518 (LINC00518) and Preferentially Expressed Antigen in (PRAME), an add-on assay for DNA promoter mutations telomerase reverse transcriptase (TERT). This registry study examines concordance PRAME detection by polymerase chain reaction (PCR) samples obtained non-invasively prior biopsy immunohistochemistry (IHC) on same lesions after biopsy.​
 Methods: Between April 2021 March 2022, multiple geographically diverse sites throughout US submitted data assess real-world use DMT. Approximately 8,000 clinically atypical were tested. After receiving result, providers followed their clinical judgement decision. When expressed genomic markers (LINC, PRAME, and/or TERT) biopsied, pathology reports also registry. presence or absence was reviewed compared PCR from DMT lesion.​
 Results: At 1-year mark registry, there roughly unique entries. Of those, 1,021 (12.8%) positive one more markers. One thousand three (98.2%) had records available. Pathologists used IHC 102 (10.2%). 40 (39.2%) IHC, 62 (60.8%) negative IHC. positivity correlated with 35 (87.5%). Conversely, detected using 28 (45.2%) where it not Conclusions: higher sensitivity may explain when than In this set, usually PCR. can still be substantial percentage cases. increased likely due several factors, including its mRNA sampling entire lesion. As such, status aid pathologists understanding risk melanoma even negative. Further research warranted understand implications versus positivity. ​