 Recently, the fusion gene EML4-ALK was identified in non-small cell lung carcinoma, which could be a potential therapeutic target.     ///    Anaplastic lymphoma kinase immunohistochemistry may have utility as a screening tool or as a surrogate marker for the molecular techniques to detect the EML4-ALK fusion gene in these tumors..     ///    "In conclusion, anaplastic lymphoma kinase immunoreactivity in non-small cell lung carcinomas was associated with transcriptional up-regulation, ALK locus rearrangement, and the presence of EML4-ALK fusion transcript. "    ///    The presence of EML4-ALK fusion transcript was confirmed in 2 cases by reverse transcriptase-polymerase chain reaction.     ///    Florescence in situ hybridization for the ALK locus and reverse transcriptase-polymerase chain reaction for EML4-ALK were performed on tumors positive for anaplastic lymphoma kinase by immunohistochemistry. 