Alterations of β-catenin can promote cancer progression, but there has been little analysis of this protein in oral squamous cell carcinoma (OSCC). The objective of this study was to investigate the role of β-catenin in OSCC development.

Expression of β-catenin and Ki-67 from 92 OSCC was immunohistochemically studied in tissues close to the tumor invasion point and, in 37 cases, in tissues distant from the invasion point.

Loss of membranous β-catenin expression was observed in 77.2% of "close" samples and 94.4% of "distant" samples. Nuclear β-catenin expression was detected in 35.9% of adjacent samples and 44.4% of "distant" samples. Nuclear β-catenin expression in ≥10% of cells was observed in 6.6% of "close" samples and 25% of "distant" samples. No relationship was found between β-catenin expression and cell proliferation.

β-Catenin plays a major oncogenic role in OSCC, principally through increase in invasiveness due to loss of its membranous expression.