Association of TP53 mutations with the expression of PD-L1 expression and TMB, and R175H could be the predictor of neoantigen.

e20530 Background: Lung cancer (LC) is the second leading causes of cancer-related mortality and composed of diverse molecular types. PD-L1 expression and tumor mutation burden (TMB) are important biomarkers of tumor immunotherapy. TP53 mutation is associated with neoantigen productions which is also involved in tumor immunotherapy. The relationship between PD-L1 expression, TMB and TP53 mutations have not yet been fully studied, and the neoantigens derived from TP53 mutations need to be explored. Methods: The total 1932 LC tissue samples (from same number of patients) in formalin fixed and paraffin embedded were collected from Guangzhou Huayin Health Medical Group Co.,Ltd. By targeting next generation sequencing (NGS) of 600 genes, the mutations of TP53 and TMB were obtained. PD-L1 expression was determined according to the tumor proportion score (TPS) evaluated by immunohistonchemistry (the cutoff of PD-L1 is greater than 1% TPS). Neoantigen predictions based on binding affinity data (https://services.healthtech.dtu.dk/service.php?NetMHCcons-1.1). In this data set, mutated peptides of TP53 with a binding affinity of IC50≤50 nM was regarded as candidate neoantigens. Results: Among 1932 samples, 890 (46%) were TP53 mutated. The positive rate of PD-L1 in TP53 mutant type (MT) group was higher than that in TP53 wide type (WT) group(p < 0.01). The WT group had a lower TMB compared with MT group (p = 0.002). The intersection of 49 candidate neoantigens and TP53 high-frequency mutation sites was R175H, which could predicate a neoantigen. Conclusions: This study determined the connection between TP53 mutations and PD-L1 expression and TMB, also made neoantigen prediction of R175H mutation. This study may provide theoretical insights for drug developments of treating lung cancer.