Rapid Intraoperative Genetic Analysis of Adult-type Diffuse Gliomas Using a Microfluidic Real-Time Polymerase Chain Reaction Device

The 5th edition of the World Health Organization Classification of Tumors of the Central Nervous System introduced a subclassification of tumors based on key molecular markers. In adult-type diffuse gliomas, isocitrate dehydrogenase (IDH) and telomerase reverse transcriptase (TERT) promoter mutations play pivotal roles in the molecular classification. This study developed a rapid genotyping system using GeneSoC®, a real-time polymerase chain reaction (PCR) platform with microfluidic thermal cycling capable of completing 50 cycles of PCR within 20 min. To establish optimal analytical conditions, frozen tumor tissues from 67 patients and artificial DNA vectors were analyzed using this system. This system demonstrated a detection limit of at least 5% variant allele frequency for the IDH1 R132H and TERT promoter C228T/C250T mutations. Subsequently, intraoperative testing was performed in 120 cases using this system. The sensitivity and specificity of IDH1 R132H mutation were 0.985 and 0.982, respectively, whereas those of TERT promoter C228T/C250T mutation were 1.000 and 1.000, respectively. These mutations were detected intraoperatively within approximately 25 min after tumor tissue collection. Furthermore, this assay identified tumor boundaries in an IDH-mutated glioma case, where IDH1 R132H mutations could not be detected. The GeneSoC®-based rapid genotyping system may be effective not only for intraoperative diagnosis of diffuse glioma but also for detecting tumor boundaries.