A 35-Gene Expression Profile Test for use in Suspicious Pigmented Lesions Impacts Clinical Management Decisions of Dermatopathologists and Dermatologists

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Aaron Farberg
Kelli Ahmed
Christine Bailey
Brooke Russell
Kelly Douglas
Clare Johnson
Olga Zolochevska
Robert Cook
Matthew Goldberg


35-GEP, melanoma, management, clinical utility, diagnostic test


Purpose: Histopathological examination is sufficient for diagnosis of many melanocytic neoplasms, however, diagnostic discordance is common between dermatopathologists. A timely and confident diagnosis is optimal, especially in cases where both benign and malignant melanocytic neoplasms are considered in the differential diagnosis as treatment plans diverge significantly.

A 35-gene expression profile (GEP) test that classifies melanocytic lesions into categories (benign, intermediate-risk and malignant), has reported accuracy metrics of 99.1% sensitivity, 94.3% specificity, 93.6% positive predictive value and 99.2% negative predictive value in a validation cohort of 503 samples. The clinical utility of the 35-GEP is described.

Methods: Dermatopathologists (n=6) and dermatologists (n=14) were queried regarding diagnostic challenges and patient management strategies in 60 difficult-to-diagnose melanocytic neoplasms. Participants reviewed each lesion twice, once without the 35-GEP result and once with. Responses were evaluated for consistent trends in the utilization of the 35-GEP test result.

Results: Dermatopathologists utilized the 35-GEP result to refine their diagnoses by increasing overall lesion diagnostic concordance and confidence, while reducing additional work up requests. Dermatologists utilized the 35-GEP result to gauge overall prognosis and case difficulty. Alterations in office visit frequency, biopsies, and referrals to specialists were also influenced by the 35-GEP result and treatment plan modifications also matched the appropriate directionality of the 35-GEP result.

Conclusions: The diagnosis of challenging melanocytic neoplasms and subsequent clinical management decisions are influenced by 35-GEP results in a manner that agrees with the test result. The utility of the test provides the opportunity to improve patient care.


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