Abstract 744: Clinically targetable genomic alterations in acral melanoma

Abstract

Abstract Background: Acral melanoma is a rare subtype of melanoma, which has a distinct genomic profile from cutaneous melanoma. While survival outcomes for late-stage cutaneous melanoma have significantly improved in the last decade, treatment options for acral melanoma remain limited. The purpose of this study was to assess therapeutically targetable genomic alterations in acral melanoma. Methods: The AACR project GENIE database was accessed via cBioPortal (http://cbioportal.org/genie/; version 3) to identify recurrent gene alterations in acral melanomas analyzed using the MSK-IMPACT oncopanel. These alterations were assessed through Cancer Genome Interpreter (http://cancergenomeinterpreter.org) to identify clinically actionable alterations. Results: Thirty-six patients with acral melanoma were identified from the cBioPortal-GENIE database. These patients were sequenced using three different versions of oncopanel, which included 341 (n = 6), 410 (n = 22) and 468 (n = 8) genes. Seventy-six genes were found to be somatically mutated in this cohort in at least one sample. The most commonly mutated genes were NF1 (n = 5), BRAF (n = 5), PTPRT (n = 4), NOTCH3, HRAS and KRAS (n = 3). Copy number variations greatly contributed to aberration burden, with 132 unique genes found to either carry an amplification or deletion event. The most commonly amplified genes were CDK4 (n = 9), CCND1 (n = 9), FGF19/FGF4 (n = 8), PAK1 (n = 8), MDM2 (n = 7) and FGF3 (n = 7). The most recurrently deleted genes included CDKN2A (n = 9) and CDKN2B (n = 8), and less commonly JAK2 and PTEN (n = 2). Some genes were altered by various mechanisms; for example, some tumors had KIT activated by amplification while other tumors carried missense mutations. BRAF exhibited two fusion events: BRAF-METTL2B (with concomitant amplification) and BRAF-KIAA1549. Cancer Genome Interpreter identified several therapeutic targets, some of which have been the focus of clinical trials in cutaneous melanoma and other solid tumors, e.g. CDK4/6 inhibitors to target amplified CDK4 and CCND1, or mTOR inhibitors for tumors with NF1 mutations. Conclusion: Several inhibitors are available which could show efficacy in a subset of acral melanomas with particular genomic alterations. Many of these inhibitors have yet to be tested in the context of acral melanoma and should be explored. Citation Format: Natasa Broit, Ken Dutton-Regester, Peter Johansson, Antonia L. Pritchard, Glen M. Boyle, Nicholas K. Hayward. Clinically targetable genomic alterations in acral melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 744.