This systematic review and meta-analysis aims to evaluate the prognostic and clinicopathological significance of the aberrant expression of β-catenin (assessed through the immunohistochemical loss of membrane expression, cytoplasmic and nuclear expression) in oral squamous cell carcinoma (OSCC). We searched for primary-level studies published before October-2021 through PubMed, Embase, Web of Science, Scopus, and Google Scholar, with no limitation in regard to their publication date or language. We evaluated the methodological quality and risk of bias of the studies included using the QUIPS tool, carried out meta-analyses, explored heterogeneity and their sources across subgroups and meta-regression, and conducted sensitivity and small-study effects analyses. Forty-one studies (2746 patients) met inclusion criteria. The aberrant immunohistochemical expression of β-catenin was statistically associated with poor overall survival (HR = 1.77, 95% CI = 1.20-2.60, p = 0.004), disease-free survival (HR = 2.44, 95% CI = 1.10-5.50, p = 0.03), N+ status (OR = 2.39, 95% CI = 1.68-3.40, p < 0.001), higher clinical stage (OR = 2.40, 95% CI = 1.58-3.63, p < 0.001), higher tumour size (OR = 1.76, 95% CI = 1.23-2.53, p = 0.004), and moderately-poorly differentiated OSCC (OR = 1.57, 95% CI = 1.09-2.25, p = 0.02). The loss of β-catenin in the cell membrane showed the largest effect size in most of meta-analyses (singularly for poor overall survival [HR = 2.37, 95% CI = 1.55-3.62, p < 0.001], N+ status [OR = 3.44, 95% CI = 2.40-4.93, p < 0.001] and higher clinical stage [OR = 2.51, 95% CI = 1.17-5.35, p = 0.02]). In conclusion, our findings indicate that immunohistochemical assessment of the aberrant expression of β-catenin could be incorporated as an additional and complementary routine prognostic biomarker for the assessment of patients with OSCC.
Keywords: CTNNB; Wnt signalling pathway; beta-catenin; biomarker; epithelial-mesenchymal transition; meta-analysis; oral squamous cell carcinoma; prognosis; systematic review; β-catenin.