Haruhiko Nakamura1, Hirotaka Koizumi2, Hiroyuki Kimura3, Hideki Marushima3, Hisashi Saji3, Masayuki Takagi2. 1. Department of Chest Surgery, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan. Electronic address: h-nakamura@marianna-u.ac.jp. 2. Department of Pathology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan. 3. Department of Chest Surgery, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan.
Abstract
OBJECTIVES: Epidermal growth factor receptor (EGFR) mutation rates in adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) were studied using both DNA analysis and mutation-specific immunohistochemistry. MATERIALS AND METHODS: The peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method was used to detect mutations in exons 18, 19, 20, and 21 of the EGFR gene in DNA samples extracted from paraffin-embedded tissue sections. Simultaneously, immunohistochemical analysis with two EGFR mutation-specific monoclonal antibodies was used to identify proteins resulting from an in-frame deletion in exon 19 (E746_A750del) and a point mutation replacing leucine with arginine at codon 858 of exon 21 (L858R). RESULTS: Forty-three tumors (22 AIS and 21 MIA) were examined. The EGFR mutation rate in AIS detected by DNA analysis was 27.3% (L858R, 5/22; exon 19 deletion,1/22), whereas that detected in MIA was 42.9% (L858R,4/21; exon 19 deletion,5/21). Mutations detected by immunohistochemical analysis included 22.7% (L858R, 4/22; exon 19 deletion, 1/22) in AIS and 42.9% (L858R, 4/21; exon 19 deletion, 5/21) in MIA. Although some results were contradictory, concordant results were obtained using both assays in 38 of 43 cases (88.4%). CONCLUSION: DNA and immunohistochemical analyses revealed similar EGFR mutation rates in both MIA and AIS, suggesting that mutation-specific monoclonal antibodies are useful to confirm DNA assay results.
OBJECTIVES:Epidermal growth factor receptor (EGFR) mutation rates in adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) were studied using both DNA analysis and mutation-specific immunohistochemistry. MATERIALS AND METHODS: The peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method was used to detect mutations in exons 18, 19, 20, and 21 of the EGFR gene in DNA samples extracted from paraffin-embedded tissue sections. Simultaneously, immunohistochemical analysis with two EGFR mutation-specific monoclonal antibodies was used to identify proteins resulting from an in-frame deletion in exon 19 (E746_A750del) and a point mutation replacing leucine with arginine at codon 858 of exon 21 (L858R). RESULTS: Forty-three tumors (22 AIS and 21 MIA) were examined. The EGFR mutation rate in AIS detected by DNA analysis was 27.3% (L858R, 5/22; exon 19 deletion,1/22), whereas that detected in MIA was 42.9% (L858R,4/21; exon 19 deletion,5/21). Mutations detected by immunohistochemical analysis included 22.7% (L858R, 4/22; exon 19 deletion, 1/22) in AIS and 42.9% (L858R, 4/21; exon 19 deletion, 5/21) in MIA. Although some results were contradictory, concordant results were obtained using both assays in 38 of 43 cases (88.4%). CONCLUSION: DNA and immunohistochemical analyses revealed similar EGFR mutation rates in both MIA and AIS, suggesting that mutation-specific monoclonal antibodies are useful to confirm DNA assay results.