Usefulness of immunohistochemistry for the detection of the BRAF V600E mutation in Japanese lung adenocarcinoma.
OBJECTIVE
Mutations in components of the mitogen-activated protein kinase (MAPK) cascade may be a new candidate for target for lung cancer. The usefulness of immunohistochemistry (IHC) as a new approach for the detection of BRAF V600E in cancer patients has been recently reported.


METHODS
To increase the sensitivity, we modified BRAF V600E expression detection assay by IHC using mutation specific antibody. From the screening step, we found a novel 599 insertion T BRAF mutation in lung adenocarcinoma. In this study included 26 surgically removed cases with EGFR, Kras, erbB2, EML4-ALK and KIF5B-RET wild-type (wt) lung adenocarcinomas, including 7 BRAF mutants (5 V600E, 1 N581I, and 1 novel 599 insertion T mutation) analyzed by DNA sequencing. Detection of the BRAF V600E mutation was carried out by the Dako EnVision™ FLEX detection system using the VE1 clone antibody and compared with the results of direct sequencing.


RESULTS
The autostainer IHC VE1 assay was positive in 5 of 5 (100%) BRAF V600E-mutated tumors and negative in 20 of 21 (95.2%) BRAF non-V600E tumors, except for a novel 599 insertion T case.


CONCLUSIONS
IHC using the VE1 clone and FLEX linker is a specific method for the detection BRAF V600E and may be an alternative to molecular biology for the detection of mutations in lung adenocarcinomas. This method might be useful for screening to use molecular target therapy for lung adenocarcinomas.
Department of Oncology, Immunology and Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. Electronic address: hisasaki@med.nagoya-cu.ac.jp.
Hidefumi
H
Sasaki
Shigeki
S
Shimizu
Yoichi
Y
Tani
Masayuki
M
Shitara
Katsuhiro
K
Okuda
Yu
Y
Hikosaka
Satoru
S
Moriyama
Motoki
M
Yano
Yoshitaka
Y
Fujii
D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D000077192:Adenocarcinoma of Lung; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007564:Japan; D008175:Lung Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000378:metabolism; D008297:Male; D025202:Molecular Diagnostic Techniques; D020125:Mutation, Missense; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012680:Sensitivity and Specificity
C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf
599 insertion T; BRAF; EnVision; IHC; Linker; Lung adenocarcinoma; V600E expression