Effect Of N-terminal Deglycosylation Modification On Expression Of PD-L1 Protein In Triple Negative Breast Cancer

Background: The most common tumor in women is breast cancer(BC).It’s become the first place in the global incidence and mortality of female cancer.Breast cancer takes a serious toll on women’s physical and mental health.The current classification of breast cancer is Luminal A,Luminal B,Her-2 and Basin-like types.The special type of breast cancer is triple negative breast cancer(TNBC),accounting for about 1/10 ～ 3/10 of all pathological types of breast cancer.Immunohistochemical examination of breast cancer tissues showed that if Progestogen receptor(PR)and Estrogen receptor(ER)were not only negatively expressed,In addition,the expression of Human epidermal growth factor receptor 2(HER-2)was also negative,so it was defined as triple-negative breast cancer.At present,six therapeutic measures mainly including endocrine therapy,targeted therapy,chemotherapy,biotherapy,radiotherapy and immunotherapy are used in the treatment of breast cancer,and achieved good curative effect.However,for triple negative breast cancer,due to the lack of clear therapeutic targets,these treatments are not effective and have a poor prognosis in clinical patients.Therefore,it is urgent to seek new methods for the treatment of triple negative breast cancer.In recent years,with the development of immunotherapy such as programmed death ligand-1(PD-L1),Programmed death Ligand-1 has brought new hope for the treatment of patients with triple negative breast cancer.However,the expression of PD-L1 in triple negative breast cancer tumor tissues is not particularly good,which makes many patients still unable to benefit from it.Existing studies have found that the expression level of PD-L1 in tumor tissues was detected again after deglycation treatment,both the expression levels of histochemistry score(H-score)and tumor proportion score(TPS)were significantly positively correlated with the efficacy of immunotherapy.That is to say,the higher the expression of PD-L1 in tumor tissues,the better the prognosis of patients after immunotherapy.However,at home and abroad,no relevant reports have been found on the effect of deglycation modification of tumor tissue on the expression level of PD-L1 protein and other clinical features in triple negative breast cancer.Objective: To detect the expression level of PD-L1 protein in triple negative breast cancer tissue,observe the effect of N-terminal deglycation modification on the expression of PD-L1 protein in triple negative breast cancer.Analyze the relationship between the expression level of PD-L1 protein and clinicopathology after deglycation modification.Explore the clinical significance of deglycation modification on the expression of PD-L1 protein in triple negative breast cancer.Method: Paraffin tissue specimens of primary tumor tissues and metastatic lymph node tumor tissues form 67 patients with triple negative breast cancer were collected.The patients were hospitalized in the Affiliated Hospital of Yangzhou University from 2019 to 2021.And those who underwent PD-L1 routine immunohistochemical En Vision staining were divided into routine group.Those who underwent immunohistochemical En Vision staining after deglycation treatment in the same tissue were divided into the deglycation group.The expression of PD-L1 in the two groups was observed under the microscope,and the difference in the expression level of PD-L1 in the two groups was compared and analyzed.And also,the relationship between the clinicopathological characteristics and the expression level of PD-L1 protein was compared and analyzed.Results: 1.The positive expression level of PD-L1 protein in primary tumor tissues and the positive expression level of PD-L1 protein in metastatic lymph node tumor tissues of 67 cases of triple negative breast cancer and the positive expression level of PD-L1 protein in the same group after deglycation were detected.The expression level of PD-L1 in the deglycation group was significantly increased compared with that in the conventional group.The positive rate of PD-L1 in primary tumor tissues increased from65.6% to 80.5%,the strong positive rate of tumor tissues increased from 35.8% to53.7%.The positive rate of PD-L1 in metastatic lymph node tumor tissues increased from 66.2% to 77.8%,and the strong positive rate of tumor tissues increased from 24.4%to 46.6%.2.There was no statistical significance in the expression of PD-L1 in primary tumor tissues between the two groups in terms of tumor diameter,degree of differentiation,clinical stage,pathological type,and lymph node metastasis(P>0.05).However,after deglycosylation,the immunohistochemical positive expression rate of PD-L1 in each clinical group was increased.The increase ranges from 5.7% to 19.1%.3.There was no statistical significance in the expression of PD-L1 in metastatic lymph node tumor tissues between the two groups in terms of lymph node diameter,metastasis classification,clinical stage,pathological type and differentiation degree(P>0.05).However,after deglycosylation,the immunohistochemical positive expression rate of PD-L1 in all clinical groups was increased.The increase ranges from 13.7% to 21.7%.Conclusion: At present,for patients with triple negative breast cancer,immunotherapy is currently the dominant treatment.But the application of immunotherapy is related to the expression of PD-L1.After deglycosylation,the positive expression rate of PD-L1 is significantly increased in both primary tumor tissues and metastatic lymph node tumor tissues,which makes part of patients with triple negative breast cancer eligible for immunotherapy,and benefit from it.