Role of Antioxidant Enzymes in Pathogenesis of Oral Squamous Cell Carcinoma: a Systematic Review and Meta-analysis

Objective: To investigate the antioxidant enzyme status in biological samples of patients with oral squamous cell carcinoma (OSCC) and compare them with biological samples of healthy people through a systematic review and meta-analysis. Methods: Antioxidant enzymes of catalase (CAT), sodium dismutase (SOD) and glutathione peroxide (GPx) were included in the analysis. A literature search was conducted of the PubMed, Science Direct, Scopus, Web of Science and Wiley Online Library databases for studies published between January 1999 and December 2022. A total of 831 articles were selected, of which 131 were found to be relevant. Finally, the full texts of 12 studies were screened and included. Studies that evaluated other antioxidant enzymes were excluded. Standardised mean difference (SMD) was derived to conduct a meta-analysis using comprehensive meta-analysis v3 (Biostat, Englewood, NJ, USA). A random effects model with 95% confidence interval (CI) was used to estimate the effect size. P < 0.05 was considered significant. Results: CAT levels were measured in eight studies (n = 567) and the mean values for the OSCC and control groups were 4.81 +/- 2.57 and 10.02 +/- 1.81, respectively (SMD 3.18, 95% CI 1.01 to 1.42; P = 0.001). SOD level was evaluated in 11 studies (n = 762) and the values for the OSCC and control groups were 3.78 +/- 1.45 and 7.34 +/- 1.79, respectively (SMD 3.66, 95% CI 1.51 to 1.94; P = 0.001).GPx level was evaluated in 10 studies (n = 697) and the values for the OSCC and control groups were 13.33 +/- 1.42 and 16.54 +/- 2.9, respectively (SMD 1.91, 95% CI 1.34 to 1.77; P = 0.001). The heterogeneity between the studies was severe (I-2 >= 90%). The risk of bias between studies was low to moderate. Conclusion: Analysis revealed that the levels of antioxidant enzymes decreased in biological samples of patients with OSSC as compared to healthy controls. Understanding the pathological progress of OSCC by analysing the level of antioxidant enzymes is beneficial in formulating a personalised, targeted pro-oxidant therapy for cancer treatment.