Immunohistochemical comparative analysis of IMP-3 and KI-67 in actinic cheilitis and lower lip squamous cell carcinoma.

Actinic cheilitis (AC) and lower lip squamous cell carcinoma (LLSCC) exhibit epithelial alterations mainly associated with chronic ultraviolet ray exposure. Currently, it is impossible to predict which AC cases will progress to LLSCC; thus, biomolecular markers have been studied. The aim of this study was to evaluate the immunoexpression of IMP-3 and KI-67 in AC and LLSCC. Forty AC and 40 LLSCC cases were submitted to peroxidase method and quantitatively analyzed, using the following scores: 0 (0% positive cells), + 1(</= 30%), + 2 (> 30% to </= 60%), and + 3 (> 60%). Results were submitted to non-parametric Mann-Whitney (U) test. A p value < 0.05 was considered to indicate statistical significance. IMP-3 immunoexpression was observed in 26 AC cases, with predominance of the score 1 (35% of cases). This protein was also positive in 22 LLSCC cases, with predominance of the score 3 (37.5% of cases). Immunoexpression of KI-67 was observed in all studied cases, with predominance of the score 2 (70% of AC cases and 57.5% LLSCC cases). The association between IMP-3 and Ki-67 immunoexpression, AC dysplastic severity and LLSCC tumoral grade revealed no significant differences. The present results demonstrate that IMP-3 and Ki-67 immunoexpression are frequent in AC and in LLSCC. Moreover, these proteins could be involved in lower lip carcinogenesis process.