[Correlation between p53 immunohistochemistry and TP53 mutations in gliomas]

Objective: To evaluate the accuracy of p53 immunohistochemistry for predicting the mutational status of TP53 in gliomas. Methods: A retrospective study was conducted on 242 diffuse gliomas diagnosed at the Department of Pathology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China from June 2022 to March 2023. All cases underwent next-generation sequencing (NGS) and p53 immunohistochemical staining. The best threshold in the percentage of p53 immunohistochemical expression was assessed as an alternative to testing for TP53 mutation. Results: Among the 242 diffuse gliomas (WHO grade 2-4), 94 cases had a TP53 mutation. The p53 immunohistochemistry results revealed a significantly increased probability of TP53 mutation when the p53 immunohistochemical positivity rate (based on strongly positive cell count) was ≥20% (P<0.05). The sensitivity and specificity of p53 immunohistochemistry for predicting TP53 gene mutations were 75.6% and 90.4%, respectively. When p53 immunohistochemical stain was totally negative, the probability of TP53 mutation increased significantly, and the mutation ratio of TP53 gene was 6/17 in all negative cases. Conclusions: When the percentage of p53 positive cells (based on strongly positive cell count) in glioma is ≥20%, p53 immunohistochemistry can be used as a reliable alternative method for TP53 mutation detection. When p53 immunohistochemistry is completely negative, the mutation rate of TP53 gene is higher, and further gene sequencing is recommended to determine the mutation status.