Study on the Relationship Between Gene Damage and PD-L1 Expression in Ovarian Cancer

HE Xiaodan; SHAN Wei; MA Yunsheng; LUO Mei

Abstract：Objective This study aims to prove the relationship between the degree of damage of gene repair function of ovarian cancer cells and PD-L1,and provide evidence for the treatment of ovarian cancer with PD-L1.Methods Tissue microarray(TMA)samples of ovarian cancer and TMA of non-small cell lung cancer were used as controls.Repair assisted damage detection(RADD)and modified RADD were used to detect DNA damage and repair function deficits.DNA damage and PD-L1 protein expression in ovarian tumor cells were observed by immunohistochemistry.Confocal laser microscopy was used to image each tissue core in TMAs.The fluorescence intensity of each core was recorded,the image was plotted and the correlation between the two was calculated.Results Both RADD method and modified RADD method could effectively detect the level of DNA damage in tumor tissues,and the modified RADD(mRADD)method had a higher detection level.There was a high incidence of oxidative DNA damage in ovarian tumors.As the level of oxidative damage to DNA increased,the expression of PD-L1 in tumors also increased.The difference in DNA damage levels between high-grade serous adenocarcinoma and endometrioid adenocarcinoma was most pronounced compared to normal tissue.Moreover,the expression of PD-L1 had a good correlation with the level of DNA damage.Correlation analysis showed that the DNA damage level of high-grade serous carcinoma and endometrioid adenocarcinoma detected by modified RADD method had a good correlation with PD-L1.The level of DNA damage in mucinous ovarian adenocarcinoma had the highest correlation with PD-L1 expression.Conclusion Oxidative damage of ovarian cancer DNA or its co-expression with PD-L1 may be a potential biomarker for improving the classification of efficacy of PD-L1 blocking therapy.