RASGRF2 gene fusions identified in a variety of melanocytic lesions with distinct morphological features

作者：Aurélie Houlier, Daniel Pissaloux, Franck Tirode, Noémie Lopez Ramirez, Maud Plaschka, Julie Caramel, Ingrid Masse, Arnaud de la Fouchardière · 发表于：Pigment Cell & Melanoma Research · 年份：2021 · DOI：10.1111/pcmr.13004 · 被引用次数：18 · 研究领域：Cutaneous Melanoma Detection and Management、Cancer Genomics and Diagnostics、Melanoma and MAPK Pathways

The WHO classification identifies nine classes of melanocytic proliferations according to location, UV exposure, histological, and genetic features. Only a minority of lesions remain unclassified. We describe five cases that harbored either an ERBIN-RASGRF2 or an ATP2B4-RASGRF2 in-frame fusion transcript. These lesions were collected from different studies, unified only by the lack of identifiable known mutations, with a highly variable phenotype. One case was a large abdominal congenital nevus, three were slowly growing pigmented nodules, and the last was an ulcerated nodule arising on the site of a preexisting small nevus, known since childhood. The latter was diagnosed as a 4 mm thick melanoma with loss of BAP1 expression. The four other cases were compound, melanocytic proliferations with an unusual deep pattern of small dense nests of bland melanocytes encased in a fibrous background. The RASGRF2 fusion was confirmed by a break-apart FISH technique. Array CGH performed in three cases found non-recurrent secondary copy number alterations. Follow-up was uneventful. In silico analysis identified a single RASGRF2 fusion in the TCGA pan-cancer database, whereas RASGRF2 variants were stochastically distributed in all cancer subtypes.