Abstract
INTRODUCTION: NTRK fusion gene-positive CNS tumours are rare and there are only two reports in Japan of the use of entrectinib, both in children; This is third case and the first adult case was experienced; the patient was treated by taking entrectinib. The diagnosis and treatment course are reported here and the problems with current oncopanel testings are discussed. CASE: Female in her 60s. She came to the hospital on her own with a chief complaint of unstable walk. A mass with a maximum diameter of 8 cm was found in the right temporal occipital lobe. She underwent craniotomy followed by radiotherapy, and in-house panel testing (PleSSision Rapid Neo) detected two BCR-NTRK2 fusion genes. Subsequently, no NTRK gene abnormalities were detected in the foundation-one. Sanger sequencing was performed by ourselves, which could still detect gene mutations, and the patient was submitted to the NCC Onco-Panel at his own expense, where NTRK fusion gene abnormalities could be detected, and after review by the in-house ethics committee, he was started on entrectinib. The tumor showed a shrinking effect and has been stable for eight months. RESULT: In the in-house panel test, NTRK2 covered Intron8,9,10,11,12 and two BCR-NTRK2 fusion genes were detected, (Exon1-Exon13) and (Exon1-Exon12). Foundation one covered Intron12 and no genetic variants were detected this time. Subsequently, the NCC OncoPanel test covered Intron 9, 10, 12, 13 and 14 and was able to detect fusion gene mutations. Different results were obtained for NTRK2 fusion gene mutations in each panel test, with different detection coverage. The differences in NTRK fusion gene mutations between tests indicate that it is important to reconfirm which panel test to choose. CONCLUSION: Third case in Japan and first adult case of NTRK fusion gene mutation-positive brain tumor; may need to be addressed in NTRK fusion gene detection, recognizing differences in cancer multi-gene panel testing.