Alectinib treatment response in lung adenocarcinoma patient with novel EML4-ALK variant.

Common gene fusion of the ALK gene is fusion of the ALK tyrosine kinase area and the 5'end of EML4. Seventeen EML4-ALK fusion variants have been reported. Herein, we report a novel EML4-ALK variant detected by next-generation sequencing in a 36-year-old female lung adenocarcinoma patient who experienced disease progression after six months of alectinib treatment. Second generation sequencing revealed an EML4-ALK fusion variant in which intron 19 of EML4 was fused to exon 20 of ALK. This is the first case of EML4-ALK (E19: A20) fusion to be reported. Alectinib may show unsatisfactory therapeutic effects for this kind of ALK fusion.