OBJECTIVES: Lung cancer with the ALK rearrangement constitutes only a small fraction of patients with non-small cell lung cancer (NSCLC). However, in the era of molecular-targeted therapy, efficient patient selection is crucial for successful treatment. In this context, an effective method for EML4-ALK detection is necessary. We developed a new highly sensitive variant specific TaqMan based real time PCR assay applicable to RNA from formalin-fixed paraffin-embedded tissue (FFPE). MATERIALS AND METHODS: This assay was used to analyze the EML4-ALK gene in 96 non-selected NSCLC specimens and compared with two other methods (end-point PCR and break-apart FISH). RESULTS: EML4-ALK was detected in 33/96 (34%) specimens using variant specific real time PCR, whereas in only 23/96 (24%) using end-point PCR. All real time PCR positive samples were confirmed with direct sequencing. A total of 46 specimens were subsequently analyzed by all three detection methods. Using variant specific real time PCR we identified EML4-ALK transcript in 17/46 (37%) specimens, using end-point PCR in 13/46 (28%) specimens and positive ALK rearrangement by FISH was detected in 8/46 (17.4%) specimens. Moreover, using variant specific real time PCR, 5 specimens showed more than one EML4-ALK variant simultaneously (in 2 cases the variants 1+3a+3b, in 2 specimens the variants 1+3a and in 1 specimen the variant 1+3b). In one case of 96 EML4-ALK fusion gene and EGFR mutation were detected. All simultaneous genetic variants were confirmed using end-point PCR and direct sequencing. CONCLUSION: Our variant specific real time PCR assay is highly sensitive, fast, financially acceptable, applicable to FFPE and seems to be a valuable tool for the rapid prescreening of NSCLC patients in clinical practice, so, that most patients able to benefit from targeted therapy could be identified.

Department of Internal Medicine Hematology and Oncology Masaryk University and University Hospital Brno Brno Czech Republic

Department of Internal Medicine Hematology and Oncology Masaryk University and University Hospital Brno Brno Czech Republic; CEITEC Central European Institute of Technology Masaryk University Brno Czech Republic

Department of Pathology Masaryk University and University Hospital Brno Brno Czech Republic

Department of Respiratory Diseases and Tuberculosis Masaryk University and University Hospital Brno Brno Czech Republic

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