Expression profile of components of the β-catenin destruction complex in oral dysplasia and oral cancer.

BACKGROUND

Oral cancer represents the sixth most common cancer in the world and is associated with 40-50% survival at 5 years. Within oral malignancies, oral squamous cell carcinoma (OSCC) is commonly preceded by potentially malignant lesions, which, according to histopathological criteria, are referred to as oral dysplasia and their diagnosis are associated with higher rates of malignant transformation towards cancer. We recently reported that aberrant activation of the Wnt/β‑catenin pathway is due to overexpression of Wnt ligands in oral dysplasia. However, the expression of other regulators of this pathway, namely components of the β-catenin destruction complex has not been explored in oral dysplasia.

MATERIAL AND METHODS

Using immunohistochemical analyses, we evaluated nuclear expression of β‑catenin and its association with Wnt3a and Wnt5a. Likewise, components of the β-catenin destruction complex, including Adenomatous Polyposis Coli (APC), Axin and Glycogen Synthase Kinase 3 beta (GSK-3β) were also evaluated in oral dysplasia and OSCC biopsies.

RESULTS

We found that moderate and severe dysplasia samples, which harbored increased expression of nuclear β‑catenin, depicted augmented cytoplasmic expression of GSK‑3β, Axin and APC, in comparison with OSCC samples. Also, GSK-3β was found nuclear in mild dysplasia and OSCC samples, when compared with other study samples.

CONCLUSIONS

Cytoplasmic levels of components of the β-catenin destruction complex are increased in oral dysplasia and might be responsible of augmented nuclear β‑catenin.