A Case Report of Acquired ALK Fusion in ALK Wild-Type Lung Adenocarcinoma Following Chemotherapy and a Literature Review Is Presented.

ALK fusion is a key driver mutation in non-small cell lung cancer, typically present as a primary genetic alteration. This article reports a rare case of a patient who was initially ALK-negative but subsequently developed an ALK fusion following chemotherapy. A 52-year-old female was diagnosed with advanced lung adenocarcinoma. Initial genetic testing showed wild-type EGFR and ALK. She received first-line platinum-based doublet chemotherapy combined with a VEGF inhibitor and a PD-L1 inhibitor, achieving a partial response. Upon disease progression, repeat genetic testing unexpectedly detected an ALK fusion. Treatment was then switched to the ALK inhibitor alectinib, and the patient again achieved a partial response. This case suggests that chemotherapy may enrich ALK fusion-positive tumour cell clones through selective pressure. These findings highlight the clinical importance of repeated genetic testing after disease progression and provide new insights for post-resistance treatment strategies.