Telomere Maintenance Associated Mutations in the Genetic Landscape of Gynecological Mucosal Melanoma

Abstract

Purpose: Gynecological melanomas (GMs) are rare tumors with a poor prognosis. Here, we performed exome sequencing to generate the mutational landscape of GMs. Methods: Next-generation sequencing was carried out on mucosal melanoma samples (n = 35) obtained from gynecological sites. The alternative telomere lengthening (ALT) phenotype was verified by fluorescence in situ hybridization and the C-circle assay. Immunohistochemistry was performed to detect ATRX protein. Copy number variations in TERT were detected by droplet digital polymerase chain reaction. Results: In the 58 formalin-fixed paraffin-embedded samples, we identified 33 (56.9%) ALT-positive cases, with 23 showing loss of ATRX protein. TERT promoter mutation was not detected in GMs (n = 40), but copy number variations in the TERT region were observed in 20% (7/35) of the samples. TERT amplification was mutually exclusive with ALT (P < 0.05). Kaplan–Meier revealed that ALT relative to TERT amplification was associated with longer overall survival in GM patients without metastasis. Conclusion: These findings indicate that telomere maintenance mechanisms play a critical role in the tumorigenesis of GMs and may aid in the prediction of clinical prognosis and the development of targeted therapy for the treatment of GM.