Abstract 5169: Sentinel lymph node gene expression signature predicts survival outcome in cutaneous melanoma

Abstract

Abstract Background: Sentinel lymph node status is an important prognostic factor for melanoma progression. We sought to develop a sentinel lymph node gene expression signature score predictive of disease progression in patients with cutaneous melanoma. Methods: Cases were retrieved from University of Pittsburgh protocol “Sentinel Node and Non-Sentinel Lymph Nodes (SLN and non-SLN) Procurement from Melanoma Subjects for Molecular Profiling.” Gene expression profiling was performed on SLN biopsies using U133A 2.0 Affymetrix gene chips. The top 25 genes associated with progression-free survival (PFS) were selected and a penalized regression function was used to select genes with a non-zero coefficient. A risk score was calculated from a 12 gene signature. A proportional hazards regression model was used to evaluate the association between clinical covariates, gene signature score, and PFS. Results: In total, 45 patients were included [female=18 (40%), median age (range)= 56 (16-81) years]. The median Breslow thickness (IQR) was 4.1 (3.3-6.0) mm, ulceration was present in 29 (67%) cases, and 25 (56%) lesions had nodular histology. Among patients, 23 (51%) had a positive SLN via H&E. Twenty-one (46.7%) patients developed disease recurrence/progression with a median follow-up of 8.3 years. The median time to progression was 9.6 years. Among the top 25 genes, 12 non-zero penalized coefficients were estimated (CLGN, C1QTNF3, ADORA3, ARHGAP8, ZNF223, PDE6G, CXCL3, CHRFAM7A, HLA-DRB-decreased risk, DCTN1, ASPSCR1, HEXIM1-increased risk). A 12-gene signature score was significantly associated with PFS (p<0.0001) and produced a bootstrap cross-validated C index of 0.888. Stratifying by SLN status the gene signature risk score remained highly significant (p<0.0001). In univariate analysis, Breslow thickness (HR=1.41), presence of ulceration (HR=3.61), SLN positivity (HR=2.50), and acral-lentiginous histology compared to nodular (HR=4.07) were each significantly associated with PFS (all p<0.05). After simultaneously adjusting for all of these factors plus the gene signature, the 12-gene score remained a significant predictor for PFS (p<0.0001). Conclusion: A SLN 12-gene signature risk score is associated with melanoma progression regardless of SLN status and can be used as a prognostic factor for PFS of patients. External validation of the gene signature is warranted. Citation Format: Lilit Karapetyan, William Gooding, Xi Yang, Andrew Knight, Aofei Li, Cindy Sander, Monica Panelli, Walter J. Storkus, Ahmad A. Tarhini, John M. Kirkwood. Sentinel lymph node gene expression signature predicts survival outcome in cutaneous melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5169.