Complex genetic alterations contribute to rapid disease progression in an ALK rearrangement lung adenocarcinoma patient: a case report

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) have been found to significantly improve the quality of life and survival in ALK-positive non-small cell lung cancer (NSCLC) patients. However, the duration of responses is limited by drug resistance. Genetic heterogeneity of ALKpositive tumors could potentially explain the differences in individual patient outcomes. We performed nextgeneration sequencing (NGS) on plasma samples, pleural effusion samples, and tissue re-biopsy obtained at various treatment milestones from an ALK rearrangement lung adenocarcinoma patient undergoing targeted therapy. The liver metastases of the EML4-ALK NSCLC patient presented rapid progression after 3.5 months of alectinib, while the other lesions showed good partial response. Targeted NGS identified the newly emerged MET amplification except for EML4-ALK in plasma ctDNA and liver lesions. Subsequently, a clinical benefit was achieved one month after the commencement of crizotinib, a dual ALK and MET inhibitor; however, the patient experienced disease progression another month later. Several rounds of ALKTKI combination therapy were tried but failed. Concurrent genetic alterations, including loss-of-function mutations in FBXW7 and MLL3, may mainly contribute to poor prognosis in the patient. It highlighted the molecular profiling by using NGS can be useful in identifying the heterogeneity across lesions and the resistance mechanism of targeted treatments. Keywords: Anaplastic lymphoma kinase (ALK); MET amplification; resistance mechanism; next-generation