PD-L1 Polymorphism Can Predict Clinical Outcome of Brazilian Non-Small Cell Lung Cancer Patients After Postoperative Adjuvant Treatment
Abstract BackgroundAlthough the incidence and mortality of non-small cell lung cancer (NSCLC) remains high with poor prognosis, programmed death‐1 (PD‐1) and programmed death‐ligand 1 (PD‐L1) pathway are promising prognostic and predictive biomarker of NSCLC. The polymorphisms on PD‐L1 gene may be associated with their protein expressions and affect the adjuvant treatment and outcome of NSCLC patients. The goal of this study was to evaluate the clinicopathologic values of PD-L1 expression and single-nucleotide polymorphisms (SNPs) in the PD-L1 gene in lung adenocarcinoma (ADC), squamous cell carcinoma (SqCC), and large cell carcinoma (LCC). MethodsThe 70 NSCLC samples consisted of 33 samples of ADC, 24 of SqCC and 13 of LCC. All tissue microarray paraffin blocks were used for PD-L1 multiplex immunofluorescence assays with Cell Signaling E1L3N clone. Fifteen polymorphisms in the PD-L1 gene were investigated by deep targeted sequencing.ResultsThe PD-L1 expression was higher in ADC than in SqCC and LCC. Three polymorphisms rs4742098, rs4143815, and rs7041009 were significantly associated with tumor recurrence (P=0.01; P=0.05; P=0.02, respectively). According to the recurrence of the disease, carriers of the G allele were less likely to relapse (P=0.01) compared to the homozygous AA genotype for rs4742098. As in rs4143815, individuals with the C allele were also less likely to relapse (P=0.05). As for rs7041009, individuals with AG or GG genotypes were more likely to relapse. The G allele of rs7041009 also showed a significant correlation with age, younger patients, 16 (41.0%) and status, among 11 (39.3%) compared to carriers of the A allele (P=0.02 and P<0.01, respectively). The rs7041009 AG genotype was inversely associated with E1L3N clone PD-L1 labeling in NSCLCs but did not reach statistical significance. Kaplan-Meier survival curves showed that the prognosis of patients with NSCLC was strongly dependent on the alternative allele G (genotype AG or GG) of rs4742098, alternative allele C (genotype CG or CC) of rs4143815 and individuals with GG genotype of rs7041009 (P=0.02; P=0.05 and P<0.01, respectively). Multivariate analysis by the Cox Regression model showed genotype GG of rs7041009 independently associated with cancer recurrence and patients without adjuvant radiotherapy (hazard ratio [HR] = 7.59, 95% confidence interval [CI] = 1.06-54.03, and HR = 9.24, CI = 1.13-75.16).ConclusionsPD-L1 rs7041009 GG polymorphisms may be useful for the prediction of clinical outcome of radiotherapy in NSCLC. Further studies are needed to confirm our findings and to understand the role of PD-L1 in the radiotherapy outcome of NSCLC patients.