Reduced Expression of Limd1 in Ulcerative Oral Epithelium Associated with Tobacco and Areca Nut

Purpose: The aim of this study was to cast light on initiating molecular events associated with the development of premalignant oral lesions induced by tobacco and/or areca nut. Method: Immunohistochemical analyses of cell cycle regulatory proteins (LIMD1, RBSP3, p16, RB, phosphorylated RB, p53), EGFR and SH3GL2 (EGFR associated protein) were performed with inflammatory/ulcerative epithelium and adjacent hyperplastic/mild dysplastic lesions. Results: No change in expression of the proteins was seen in inflammatory epithelium. Reduced nuclear expression of LIMD1 was evident in ulcerative epithelium. In hyperplastic lesions, reduced expression of RBSP3, p16, SH3GL2 and overexpression of p-RB and EGFR were apparent. Reduced nuclear expression of p53 was observed in mild dysplastic lesions. Conclusion: Our data suggest that inactivation of LIMD1 in ulcerative epithelium might predispose the tissues to alterations of other cell cycle regulatory and EGFR signaling proteins needed for the development of premalignant oral lesions.