RESUMEN
BACKGROUND: Numerous attempts have been made to establish and develop tumor markers that could determine the susceptibility of normal tissues to transform into cancerous ones. To determine whether altered expression patterns of E-cadherin could be an early event in the progression of potentially malignant disorders to oral squamous cell carcinoma, this study aimed to assess the relationship between the immunoexpression of E-cadherin and the different degrees of epithelial dysplasia in oral leukoplakia. METHODS: Surgically excised specimens from patients with oral leukoplakia (n=31), oral cavity squamous cell carcinoma with cervical lymph node metastasis (n=12) and normal oral mucosa (n=9) were immunostained for E-cadherin. Oral leukoplakia samples were distributed into low and high risk group according to a binary system for grading oral epithelial dysplasia. Comparative analyses between E-cadherin expression and microscopic features (WHO histological grading and epithelial dysplasia) were performed by Pearson Chi-square test (P<0.05). RESULTS: Differences in E-cadherin expression were observed between normal oral mucosa and low risk oral leukoplakia (P=0.006), low and high risk oral leukoplakia (P=0.019), and high risk oral leukoplakia and oral cavity squamous cell carcinoma with cervical lymph node metastasis (P=0.0001). In addition, as epithelia undergo dysplastic changes, the risk of malignant transformation increases, and there is a reduction or loss of E-cadherin expression by keratinocytes. Reduced E-cadherin expression was an early phenomenon and it was observed in moderate-severe dysplasia, showing that the loss of epithelial cohesion may be an indicator of progression to oral cavity squamous cell carcinoma. CONCLUSIONS: E-cadherin could be used as a novel biomarker to identify lesions with potential risk for malignant transformation, which may provide opportunities for prophylactic interventions in high risk patient groups.