Recent studies reported the expression of anaplastic lymphoma kinase (ALK) in malignant melanomas. The aim of this study was to investigate whether ALK expression is associated with specific clinical and molecular characteristics of melanoma metastases, and to evaluate its correlation with survival outcomes. Seventy-one patients with metastatic melanoma were investigated. Clinical features and survival outcomes were analyzed and correlated to ALK expression, as detected by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction, and to the mutational status of BRAF, KRAS, NRAS, and PIK3CA. No translocations or ALK alternative isoforms were identified. ALK expression was mainly detected in NRAS mutated metastatic lesions. Interestingly, among NRAS-mutated patients, ALK positive samples displayed a significantly more favorable outcome in terms of disease specific survival, as compared to ALK negative ones. In conclusion, we suggest that ALK positive/NRAS mutated metastases represent a specific subset of metastatic melanomas, associated with a better prognosis. Validation of these observations in larger cohorts could contribute to understand the molecular events cooperating to melanoma progression, in addition to open new perspectives in the clinical and therapeutic management of this subgroup of patients.
Keywords: ALK; NRAS; metastatic melanoma.