Correlation between expression of ovarian tumor domain-containing ubiquitin aldehyde binding protein 1 and programmed cell death-ligand 1 in non-small cell lung cancer

Objective To explore the correlation between ovarian tumor domain-containing ubiquitin aldehyde binding protein 1 (OTUB1) and programmed cell death-ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC).

Methods Differences of OTUB1 mRNA between NSCLC and corresponding non-tumor normal tissues in the Cancer Genome Atlas (TCGA) were analyzed. The correlation on mRNA expression between OTUB1 and PD-L1 in NSCLC in Gene Expression Profiling Interactive Analysis (GEPIA) was discussed. The protein expressions of OTUB1 and PD-L1 in 46 cases of NSCLC and 41 cases of corresponding non-tumor normal tissues were detected by immunohistochemistry, and the clinical case data and follow-up data were collected. The expression difference of OTUB1 between cancer tissues and adjacent tissues, the correlations between OTUB1 and PD-L1 as well as clinicopathological features, and the predictive significance for recurrence free survival (RFS) were analyzed.

Results There were significant differences in mRNA and protein expressions of OTUB1 between NSCLC and corresponding non-tumor normal tissues (P < 0.05). There was no correlation in mRNA expression between OTUB1 and PD-L1 in NSCLC tissues (P>0.05), but there was a correlation in protein expression between OTUB1 and PD-L1 (P=0.029). OTUB1 was correlated with TNM staging (P=0.039), but had no correlation with age, history of smoking, degree of differentiation, number of metastatic lymph nodes and pathological type (P>0.05). Kaplan-Meier analysis showed that TNM staging (P < 0.001), the number of metastatic lymph nodes (P=0.001) and the degree of differentiation (P=0.042)were the influencing factors of RFS. The median RFS of negative and positive OTUB1 were 18 months and 19 months, respectively, and there was no significant difference (P>0.05). COX multivariate analysis showed that the degree of differentiation (P=0.005) and TNM staging (P=0.006) were the independent risk factors for RFS.

Conclusion The mRNA and protein expression levels of OTUB1 in NSCLC tissue are higher than those in corresponding non-tumor normal tissues. In terms of protein level, OTUB1 is positively correlated with PD-L1. OTUB1 expression is related to TNM staging.