Immunohistochemical Expression of PD-L1 and IDH1 with Detection of MGMT Promoter Methylation in Astrocytoma

Abstract

Objective: Programmed death ligand 1 (PD-L1) expression was suggested as a poor prognostic predictor for glioblastoma. While isocitrate dehydrogenase (IDH) has been linked to enhanced overall survival in glioma cells. In glioblastoma patients receiving treatment with alkylating drugs, the methylguanine-DNA methyltransferase (MGMT) promoter's methylation status has been discovered as a potent and distinct predictor of good survival. In this study, we aimed to investigate the expression rate of PD-L1, IDH1, and MGMT methylation in patients with different grades of astrocytoma. Methods: The present retrospective study retrieved the data and archived paraffin blocks of 60 cases of astrocytoma. Immunohistochemical evaluation was done to assess the expressions of PD-L1 and IDH1, Methylationspecific-PCR was used to investigate the MGMT promoter. Results: This study included astrocytoma 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). High grade astrocytoma showed highrer expression of PD-L1 & IDH1 but with insignificant correlation (p=0. 989). Conclusion:There is a relatively high expression of PD-L1 and IDH1 in patients with astrocytoma. More than half of the patients presented with MGMT promoter methylation. Further studies with larger sample size are required to investigate the association between these biomarkers and characteristics of patients with astrocytoma.

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“…The protein catalyzes the transfer of methyl groups from O(6)-alkylguanine and other methylated moieties of the DNA to its own molecule, which repairs the toxic lesions. Methylation of the MGMT promoter or inactivating mutations have been associated with several cancer types, including colorectal cancer, lung cancer, prostate cancer, lymphoma, glioblastoma, and astrocytoma [62][63][64].…”