Expression of adhesion proteins (E-cadherin and β-catenin) and cell proliferation (Ki-67) at the invasive tumor front in conventional oral squamous cell and basaloid squamous cell carcinomas.

Objective: Investigate, on a comparative basis, the expression of the adhesion molecules E-cadherin (E-cad), β-catenin (β-cat) and the proliferation index (Ki-67) at the invasive tumor front (ITF) in squamous cell carcinoma (SCC) and basaloid squamous cell carcinoma (BSCC).

Material And Methods: Thirty-five SCC and 16 BSCC cases were evaluated by immunohistochemistry. Clinicopathological and survival data were also evaluated and compared.

Results: There was a low expression of E-cad in the cytoplasmic membrane (p=0.50) as well as in the nucleus (p=0.31) for both SCC and BSCC. A high expression of E-cad was seen in the cytoplasm for the SCC group (80%) when compared to the BSCC group (25%) (p<0.01). The expression of β-cat was low in the cytoplasmic membrane and high in the cytoplasm in both SCC and BSCC groups. Both types of carcinoma presented low expressions of β-cat in the nucleus (p=0.03). The Ki-67 expression was low irrespective of tumor variant. The high expression of E-cad in the cytoplasm was associated with T3/T4 tumors (p=0.04) in the SCC group and there was no significant association of E-cad, β-cat, Ki-67 with the other clinical variables. In terms of disease-free survival and overall survival, there were no significant differences between SCC and BSCC.

Conclusion: The E-cad-β-cat system was found to be dysregulated in both oral SCC and oral BSCC. The Ki-67 cell proliferation index was extremely low in the cases investigated and consequently had no prognostic value.