Path-44. intra-operative analyses of genetic alterations in the central nervous system tumors using rapid quantitative pcr device

Abstract Recent comprehensive molecular analyses of central nervous system (CNS) tumors identified several diagnostic or prognostic markers. IDH mutation, TERT promoter (pTERT) mutation and CDKN2A homozygous deletion in adult-type diffuse gliomas, BRAF p.V600E mutation in circumscribed astrocytic gliomas, histone H3 gene mutations in pediatric-type diffuse high-grade gliomas or MYD88 mutation in primary CNS lymphoma (PCNSL) are quite important markers. Intra-operative identification of these molecular alterations could be effective for decision-making of tumor removal strategy. In this study, we established intra-operative gene analysis method using rapid quantitative PCR device, GeneSoC, by which we could obtain genotype of these important genes for 20 minutes in an operating room. Using GeneSoC, we could perform 50 cycles of quantitative PCR for approximately 12 minutes. We established rapid gene analyses of mutations of IDH1 p.R132H, pTERT C225T, pTERT C250T, H3 K27M, BRAF p.V600E and homozygous deletion of CDKN2A for diffuse gliomas and circumscribed astrocytic tumors and MYD88 p.L265P for PCNSL. For elution of DNA, we incubated at least 1mg of tumor tissue at 95°for 5 minutes. Combined this boiling method with GeneSoC, we could obtain those genetic alterations for 20 minutes after collection of tumor tissue. For 42 glioma cases and 10 PCNSL cases, we could obtain accurate genetic alterations (IDH1 p.R132H, pTERT C225T, pTERT C250T for gliomas or MYD88 p.L265P for PCNSL) in all cases, using this method. For detection of CDKN2A homozygous deletion, sensitivity and specificity are 100% and 83% in analyzed 50 cases, respectively. In this study, we could obtain the genotype of important molecular markers intra-operatively, not only during tumor removal but even during tumor biopsy, using GeneSoC device. This rapid genetic analysis might be effective not only for intra-operative diagnosis but also for detection of boundary between tumor and normal tissue.