Chao Zhao¹, Xuefei Li¹, Chunxia Su², Shengxiang Ren², Xiaoxia Chen²

¹Immune Laboratory of Lung Cancer, Shanghai Pulmonary Hospital, Shanghai. ²Departmentof Oncology, Shanghai Pulmonary Hospital, Shanghai.

Objective: EML4-ALK fusion positive non-small cell lung cancer (NSCLC) patients benefit fromcrizotinib treatment. However, the fusion rate of different types of EML4-ALK and whether they have different clinical effect have not been studied. Method: In this study, EML4-ALK fusion was detected in 68 patients (2 were NSCLC, 1 was squamous lung cancer, 1 was adenocarcinoma/squamous lung cancer, and 64 were adenocarcinoma lung cancer) using amplification refractory mutation system (ARMS) method, and were confirmed by direct sequencing, which showed the fusion type. The performance status score was 0-2, and 1 patient was with score 3.Tumor response was assessed using response evaluation criteria in solid tumors (RECIST Version 1.1). Result: In the 68 patients, 28 showed EML4 exon13 fusion with ALK exon20 (41.2%), 25 EML4 exon6 fusion with ALK exon20 (36.8%), 12 EML4 exon20 fusion with ALK exon20 (17.6%), 4 EML4 exon18 fusion with ALK exon20 (5.9%) and 1 EML4 exon2 fusionwith ALK exon20 (1.5%). Two patients showed 2 fusion types. The different fusion types have no significant difference with patients^, sex, age, smoking status and brain metastasis. They also have no significant difference with patients response to crizotinib in the first-line treatment (10 patients) or other line treatment (9 patients), as well as first-line chemotherapy. Two adenocarcinoma patients had disease-free survival of 4.2 and 9.2 months, respectively. Conclusion: EML4 exon13 and 6 have high fusion rate with ALK exon20. Whether the different EML4-ALK fusion type patients have different response to crizotinib needs further study.

Key Words: lung cancer  ALK  crizotinib