The relationship between PD-L1 statusandradiosensitivity of breast cancer / 医学研究生学报

ABSTRACT

Objective Programmed cell death ligand 1 (PD-L1) plays an important role in the treatment of malignant tumors. Thestudy explores the relationship between PD-L1 status and breast cancer radiotherapy and clinical prognosis. Methods Using the Cancer Genome Atlas (TCGA) database analyze the relationshipof PD-L1 expression, radiotherapy and prognosis in breast cancer. 1007 patients were included in the statistical analysis. Based on the median value of CD274 mRNA expression levels in the database, the total sample was divided into a PD-L1 -high state group (503 cases) and a PD-L1-low state group (504 cases). Survival analysis was carried out for patients in the high and low state group with and without radiotherapyrespectively. Results The univariate analysis showed that the overall survival rate was improved in patients with PD-L1high status compared with patients with PD-L1-low status. The difference was statistically significant(P=0.047). InPD-L1-high status group, univariate analysis and multivariate analysis showed no significant difference in the overall survival rate between patients with radiotherapy and without radiotherapy, and the P values were 0.352 and 0.242 respectively. However, the overall survival rate of radiotherapy patients with PD-L1-low status group was significantly improved （HR0.550, 95%CI:0.335～0.904, P=0.017）, and there was still statistical significance after multivariate factors adjustment （HR0.415, 95%CI:0.194～0.872, P=0.025）. Chi-square analysis showed that PD-L1 status was associated with ER status (χ2=18.44，P<0.001), HER2 status （χ2=7.943，P=0.047） and molecular typing (χ2=14.52，P=0.006), but not with age, histological type, surgical treatment, postoperative tissue margin status and PR status. Conclusion The PD-L1 status was associated with the radiosensitivity of breast cancer. The overall survival rate of postoperative radiotherapy in patients with PD-L1⁃low expression was significantly improved.It is speculated that PD-L1 may be a radiosensitivity gene for breast cancer.