EGFR and invasive carcinoma: Number of tumors per cheek, volume, histological condition, erbB expression were determined and results were analyzed by the Mann–Whitney U and Dunn’s test.Results: Control groups and those exposed to alcohol (A, B and C respectively) only presented clinical and histological normal mucosa; while those exposed to DMBA or DMBA plus alcohol (D and E groups) developed dysplasia and invasive carcinomas.