To identify the role of EML4-ALK fusion oncogene in stem-like properties of NSCLC cells, we performed a tumorosphere-forming assay using four different lung epithelial cell lines, including primary and immortalized human bronchial epithelial cells (BEAS-2B), EML4-ALK− NSCLC cells (A549), and EML4-ALK+ NSCLC cells (EML4-ALK variant 1 (EAV1)-expressing H3122 and EML4-ALK variant 3 (EAV3)-expressing H2228). Here, EML4 is linked to non-small cell lung carcinoma.