A rare double ALK fusion variant EML4-ALK and CDK15-ALK in lung adenocarcinoma and response to crizotinib A case report

Rationale: The anaplastic lymphoma kinase (ALK) fusion has been identified to be a driver gene in lung cancer, and serves as important diagnostic and therapeutic targets. Owing to the advanced sequencing technologies, new partner genes of ALK have been constantly detected. Patient concerns: A 55-year-old Chinese woman went to our hospital because of cough and expectoration for 1 year. The patient had no fever, chest pain and hemoptysis. Diagnoses: She was diagnosed with lung adenocarcinoma. Because she had no operational condition, combination chemotherapy with docetaxel and cisplatin (CP) for 4 cycles was adopted. However, computed tomography (CT) scan indicated progression disease (PD). To explore possibility of targeted therapy, the tumor samples were subjected to next-generation sequencing (NGS), and a rare double ALK fusion variant EML4-ALK and CDK15-ALK was identified. Interventions and outcomes: The patient subsequently received crizotinib treatment, and achieved partial response (PR). No significant drug related adverse reactions were found during crizotinib treatment. The progression-free survival achieved 23 months. Lessons: Together, we identified a rare double ALK fusion variant, EML4-ALK and CDK15-ALK, in a patient with lung adenocarcinoma. The patient benefited from crizotinib treatment, which could provide a certain reference for the patients with such gene alteration.