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Medline ® Abstract for Reference 14

of 'Anaplastic lymphoma kinase (ALK) fusion oncogene positive non-small cell lung cancer'

Multiplex reverse transcription-PCR screening for EML4-ALK fusion transcripts.
Takeuchi K, Choi YL, Soda M, Inamura K, Togashi Y, Hatano S, Enomoto M, Takada S, Yamashita Y, Satoh Y, Okumura S, Nakagawa K, Ishikawa Y, Mano H
Clin Cancer Res. 2008;14(20):6618.
PURPOSE: EML4-ALK is a fusion-type protein tyrosine kinase that is generated by inv(2)(p21p23) in the genome of non-small cell lung cancer (NSCLC). To allow sensitive detection of EML4-ALK fusion transcripts, we have now developed a multiplex reverse transcription-PCR (RT-PCR) system that captures all in-frame fusions between the two genes.
EXPERIMENTAL DESIGN: Primers were designed to detect all possible in-frame fusions of EML4 to exon 20 of ALK, and a single-tube multiplex RT-PCR assay was done with total RNA from 656 solid tumors of the lung (n = 364) and 10 other organs.
RESULTS: From consecutive lung adenocarcinoma cases (n = 253), we identified 11 specimens (4.35%) positive for fusion transcripts, 9 of which were positive for the previously identified variants 1, 2, and 3. The remaining two specimens harbored novel transcript isoforms in which exon 14 (variant 4) or exon 2 (variant 5) of EML4 was connected to exon 20 of ALK. No fusion transcripts were detected for other types of lung cancer (n = 111) or for tumors from 10 other organs (n = 292). Genomicrearrangements responsible for the fusion events in NSCLC cells were confirmed by genomic PCR analysis and fluorescence in situ hybridization. The novel isoforms of EML4-ALK manifested marked oncogenic activity, and they yielded a pattern of cytoplasmic staining with fine granular foci in immunohistochemical analysis of NSCLC specimens.
CONCLUSIONS: These data reinforce the importance of accurate diagnosis of EML4-ALK-positive tumors for the optimization of treatment strategies.
Division of Pathology, The Cancer Institute, Tokyo, Japan. kentakeuchi-tky@umin.net