Diagnostic method for the detection of KIF5B-RET transformation in lung adenocarcinoma.
KIF5B-RET fusions have recently been reported to occur in pulmonary adenocarcinomas, thereby being proposed as a novel genetic alteration in adenocarcinoma of the lung. However, clinically useful methods to detect RET-rearrangement in pulmonary adenocarcinoma have not been well established. 53 cases of lung adenocarcinomas harbored "triple (EGFR, KRAS and ALK)-negative" were tested for KIF5B-RET fusions using whole-transcriptome sequencing, fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), and long-range PCR. Dual color break-apart probes and KIF5B-RET fusion probes were used for FISH. Three different commercial antibodies against C-terminal RET protein were tested for IHC. Primers designed for 3 different variants of KIF5B-RET fusions were used for long-range PCR. Three patients (5.6%) showed RET rearrangement in whole-transcriptome sequencing, which were used as a gold standard. All those three patients were also positive in FISH for both KIF5B-RET fusion and RET break-apart probes. None of remaining patients showed positive result, resulting in 100% concordance rate of FISH and transcriptome sequencing methods. However, fused RET proteins were not detected by IHC in none of true positive patients. Moreover, 6 patients without RET fusions showed gain of gene copy number of both KIF5B and RET. All those three true positive cases were detected by long-range PCR methods and none with true negative cases were positive. Both FISH and PCR may be useful methods to detect novel KIF5B-RET rearrangements in pulmonary adenocarcinomas rather than IHC. However, as there may be additional variant of fusion mutation, FISH may be better than PCR method in terms of sensitivity.
Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea.
Heounjeong
H
Go
Yoo Jin
YJ
Jung
Hyun Woong
HW
Kang
In-Kyu
IK
Park
Chang-Hyun
CH
Kang
Jung Wan
JW
Lee
Young Seok
YS
Ju
Jeong-Sun
JS
Seo
Doo Hyun
DH
Chung
Young Tae
YT
Kim
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics; D000077192:Adenocarcinoma of Lung; D000368:Aged; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D016547:Kinesins / Q000235:genetics*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016133:Polymerase Chain Reaction; D051096:Proto-Oncogene Proteins c-ret / Q000235:genetics*; D017422:Sequence Analysis, DNA; D059467:Transcriptome
C488101:KIF5B protein, human; D015514:Oncogene Proteins, Fusion; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D016547:Kinesins
Biomarkers; Fluorescence in situ hybridization (FISH); Immunohistochemistry (IHC); Lung cancer; Polymerase chain reaction (PCR)