 A fusion gene, echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK), with transforming activity has recently been identified in a subset of non-small cell lung cancer (NSCLC), but its pathogenetic, diagnostic, and therapeutic roles remain unclear.     ///    "In cases carrying the fusion transcript, we determined EML4-ALK gene and protein levels using fluorescence in situ hybridization, Western blotting, and immunoprecipitation. "    ///    EML4-ALK rearrangement in non-small cell lung cancer and non-tumor lung tissues..     ///    Fluorescence in situ hybridization analysis of cases expressing EML4-ALK transcripts showed that only a minority of cells harbored the EML4-ALK gene.     ///    The EML4-ALK transcript cannot be regarded as a specific diagnostic tool for NSCLC.     ///    Both frequency and type of EML4-ALK transcripts were investigated by reverse transcription PCR in 120 frozen NSCLC specimens from Italy and Spain.     ///    EML4-ALK transcripts (variants 1 and 3) were detected in 9 of 120 NSCLC samples but were not specific for NSCLC since they were also found in non-cancerous lung tissues taken far from the tumor.     ///    Our results show therefore that the causal role and value of EML4-ALK as a therapeutic target remain to be defined..     ///    "None of these cases was found to express the EML4-ALK protein as examined by immunohistochemistry, Western blotting, and immunoprecipitation. "