TB-9 An attempt to establish a patient-derived brain tumor culture model by organoid culture method

Background: Molecular heterogeneity among and within tumors are one of the reasons for the poor survival rate of brain tumors even with the current standard therapy. However, monolayer culture and neuro-sphere culture (NS) use exogenous growth factors, so may not show the true nature of the tumor. And the culture establishment rate is low, especially low-grade tumors. Therefore, we used the glioblastoma organoid (GBO) culture method showed by Fadi to create culture models of various brain tumors and investigated their characteristics. Methods: We examined the establishment rate in pathological and genotypic types of 56 patients who underwent brain tumor resection at our hospital between January 2020 and June 2021 and were cultured with GBO or NS. If tumor cells are increased visually at 1 month after culture, we defined establishment. Results: There were 15 cases of glioblastoma, 7 cases of anaplastic astrocytoma, 7 cases of diffuse astrocytoma, 3 cases of diffuse midline glioma, 2 cases of anaplastic oligodendroglioma, 5 cases of oligodendroglioma, and 16 cases of others. The establishment rate was 76.5% by the GBO method and 40% by the N S method. By histological type, GBO: 80% in glioblastoma, NS: 58.3% in glioblastoma, GBO: 83.3% in AA, NS: 40% in AA, and GBO: 100% in DA. The IDH mutation and pTERT mutation were investigated in GBO: IDHwt/TERT+ 87.5%, IDHwt/TERT- 64.3%, IDHmt/TERT- 100%, and in NS: IDHwt/TERT+ 75%, IDHwt/TERT- 33.3%, IDHmt/ TERT- 20% in NS. In addition, establishment was observed in GBO 2 case in medulloblastoma, 1 case in ependymoma. Discussion and Conclusion: This suggest that GBO can be used to establish culture models for low-grade tumors. In addition, GBO can establish culture earlier, so it is expected to be applicable to personalized therapies such as preclinical drug efficacy studies tailored to individual patients.