Mu Opioid Receptor MRNA Overexpression Predicts Poor Prognosis Among 18 Common Solid Cancers: A Pan-cancer Analysis

Background: Opioids are widely used for patients with solid tumors during surgery and for cancer pain relief. We conducted a pan-cancer genomic analysis to investigate the prognostic features of Mu opioid receptor () mRNA expression across 18 primary solid cancers.

Methods: All the data of cancer with mRNA were retrieved from cBioPortal for Cancer Genomics. Logistic regression was used to determine the associations between mRNA expression and clinicopathological features. Log-rank test and Cox regression was used for survival analysis. Subgroup analysis and propensity score matching were also carried out.

Results: 7,274 patients, including 1,112 patients with positive mRNA expression, were included for data analyses. Positive mRNA expression was associated with more advanced stage of T (adjusted Odds ratio [OR], 1.176; 95% confidence interval [CI], 1.022-1.354; =0.024), M (adjusted OR, 1.548; 95% CI, 1.095-2.189; =0.013) except N (adjusted OR, 1.145; 95% CI, 0.975-1.346; =0.101), and worse prognosis for overall survival (Hazard ratio [HR] 1.347, 95% CI 1.200-1.512, <0.001), progression-free survival (HR 1.359, 95% CI 1.220-1.513, <0.001), disease-free survival (HR 1.269, 95% CI 1.016-1.585, <0.001) and disease-specific survival (HR 1.474, 95% CI 1.284-1.693, <0.001). Patients with positive mRNA expression tended to be classified as tumor microenvironment immune types II, representing low PD-L1 and low CD8A expression.

Conclusion: mRNA overexpression is associated with poor prognosis and poor response to PD-L1 therapy.