Targeting SLMAP-ALK—a novel gene fusion in lung adenocarcinoma

Assessment of ALK gene rearrangements is strongly recommended by the Molecular Testing Guideline for Selection of Lung Cancer Patients proposed by IASLC, AMP, and CAP at the time of diagnosis for patients with advanced stage disease. Non-small-cell lung cancer (NSCLC) with ALK gene rearrangements or the resulting fusion proteins have been, for the most part, successfully targeted with ALK tyrosine kinase inhibitors (TKIs). The most frequent rearrangement, the EML4-ALK oncogenic fusion, has more than 10 distinct variants, each with a discrete breakpoint in EML4. Recent studies have suggested that EML4-ALK variants may have differential responses to TKIs. Additionally, non-EML4-ALK fusions that result from ALK rearrangements with diverse 5′ partners could possibly have varied biologic and clinical implications in their therapeutic responses and outcomes of patients with NSCLC. Existing literature documents at least 20 non-EML4 fusion partners for ALK, and the clinical responsiveness to crizotinib ranges from increased sensitivity to resistance. This underscores the importance of identifying the precise 5′ fusion partner to ALK before initiation of therapy. Herein we report the identification of a novel SLMAP-ALK fusion in a patient with NSCLC.