Predictive Value And Mechanism Of Programmed Death Ligand 1 In Neoadjuvant Therapy In Breast Cancer

Part IObjectives: We aim to determine whether the expression of programmed death-ligand-1(PDL1)protein is related to the response of patients to neoadjuvant therapy and survival outcome.Methods: Immunohistochemistry(IHC)was performed on paraffin-embedded tumor samples from core needle biopsy before neoadjuvant therapy(NAT).Univariate and multivariate logistic regression were used to analyze the associations between PDL1 protein expression and pathological complete response(p CR)outcome.Kaplan-Meier plot and log-rank test were used to compare disease free survival(DFS)between groups.Cox proportional hazards model was used to calculate the adjusted hazard ratio(HR)with 95% confidential interval(95%CI).Results: A total of 93 patients were included for IHC testing.PDL1 protein expression was associated with better p CR rate in both univariate(OR=2.621,p=0.043)and multivariate(OR=3.595,p=0.029)logistic regression analysis.It was also associated with shorter disease free survival(DFS)both by log-rank test(p=0.015)and cox hazard model(HR=22.824,95%CI 1.621-321.284,p=0.020).In hormone receptor positive patients,PDL1 protein expression was also associated with better p CR(OR=2.362,p=0.022).It was also associated with poor DFS(HR=18.821,95%CI 1.645-215.330,p=0.018).Conclusions: Our result showed that PDL1 protein expression was associated with p CR result from neoadjuvant therapy and DFS in breast cancer patients and HR positive subtypes.Part IIObjectives: We aim to determine whether single nucleotide polymorphism(SNP)in PDL1 gene is related to the response of patients to neoadjuvant therapy and survival outcome.Methods: SNPs located at the noncoding region of PDL1 gene(rs822336,rs822337,rs10815225,rs2282055,rs2297136,rs4143815,rs4742098,rs7864231)were selected and then tested using matrix-assisted laser desorption ionization-time of flight mass spectrometry method,using whole blood samples from patients before NAT.Univariate and multivariate logistic regression were used to analyze the associations between different SNP genotypes,haplotypes and pathological complete response(p CR)outcome.Kaplan-Meier plot and log-rank test were used to compare disease free survival(DFS)between groups.Cox proportional hazards model was used to calculate the adjusted hazard ratio(HR)with 95% confidential interval(95%CI).Spearman correlation test was used to determine the correlations between different genotypes and adverse events.Results: A total of 145 patients were included for SNP testing.Of all the 9 SNP loci examined,rs4143815C>G was associated with better p CR rate when tested by addictive(OR1=9.284,p1=0.049;OR2=13.501,p2=0.023)and overdominant(OR=2.800,p=0.042)model.It was also associated with shorter DFS both for log-rank test(p=0.01)and cox hazard model when tested by recessive model(HR=20.098,95%CI2.774-145.596,p=0.003).In HR positive patients,rs4143815C>G was associated with better p CR rate in univariate overdominant(OR=3.576,p=0.031)model.It was also associated with poor DFS when tested by recessive model(HR=10.781,95%CI1.578-52.777,p=0.008).Patients with rs4143815 CC+CG genotypes were more likely to suffer from neutropenia than those with GG genotype(rho=-0.183,p=0.032),but were less likely to have edema(rho=0.179,p=0.036).Compared with CG patients,CC+GG was more likely to have elevated aspartate aminotransferase(rho=-0.186,p=0.030).Conclusions: Our result showed that PDL1 single nucleotide polymorphism at rs4143815 was associated with p CR result from neoadjuvant therapy and DFS in breast cancer patients and HR positive subgroup.Part IIIObjectives: We aim to explore the potential regulation of PDL1 SNP and protein.Methods: NCBI/TCGA database and Targetscan website were used to find the potential micro RNA(mi RNA)that regulates PDL1.Overexpression of the targeted mi RNA in MDA-MB-231 and MCF-7 cell line was carried out using mi RNA mimics.Q-PCR was preformed to detect the change of PDL1 expression.Results: Rs4143815 was predicted to be located at 400 bp upstream of the potential binding site of mi R34 c and 3'UTR of PDL1 m RNA by Targetscan website and NCBI database.Negative correlation of mi R34 c and PDL1 expression was observed using TCGA database(p<0.05).Overexpression of mi R34 c resulted in the down regulation of PDL1 m RNA expression.Conclusions: We defined a negative correlation between the expression of mi R34 c and PDL1.The interaction between mi R34 c and PDL1 might be affected by rs4143815,which could be a potential therapeutic target.