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Abstract Introduction: astrocytomas are the most occurring malignant brain tumors. Programmed cell death {u2013} ligand (PD-L1) is an immune checkpoint molecule responsible for immune evasion in several other cancers. Recently, Isocitrate dehydrogenase 1 (IDH1) mutation has been included in World Health Organization (WHO) classification. We aimed to detect PD-L1 expression, IDH1 and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in astrocytic tumors. Method: This is retrospective study including 60 paraffin blocks of astrocytoma collected from department of pathology at the Kasr el Aini hospital in the time period between December 2018 and December 2019. Immunohistochemical staining by PD-L1 & IDH1 as well as detection of MGMT promoter methylation by methylation specific- polymerase chain reaction (MS-PCR). Results: this study included grade II 18% (11/60), grade III 22% (13/60), grade IV 60% (36 cases). PD-L1 expression was detected in 82% of all studied cases (49/60) while IDH1 mutant astrocytoma were 73% (44/60) & methylation was reported in 58.3% (35 cases). Higher expression of PD-L1 was noticed among recurrent glioblastoma (100%, 7/7), IDH1 mutant cases (86.4%, 38/44) & methylated cases (63.6% 31/49), but with insignificant correlation (p= 0.317, p= 0.143, p= 0.102 respectively). Conclusion: IDH1 mutant astrocytoma showed higher PD-L1 expression & MGMT promoter methylation.These cases might benefit from immunotherapy & IDH inhibitors in addition to standard treatment modalities (surgery, radiotherapy & chemotherapy) |