From laryngeal epithelial precursor lesions to squamous carcinoma of the larynx: the role of cell cycle proteins and β-catenin.

Novel markers to accurately predict the risk of malignant transformation in laryngeal epithelial precursor lesions (EPL) are needed. We tried to identify some molecular alterations occurring in laryngeal tumorigenesis. In this study, 60 paraffin-embedded EPL and 17 metachronous invasive carcinomas were immunostained for markers associated with proliferation (Ki67), cell cycle control (p53, p21, p16, p27, cyclin D1), and cell adhesion and invasion (laminin and β-catenin). Aberrant expression of p16 and p53 and positivity at cytoplasm for β-catenin and cyclin D1 were detected significantly in EPL with progression to invasive laryngeal carcinoma. All cases with basal and suprabasal reactivity of p53 showed β-catenin overexpression. We found that β-catenin protein expression increased significantly with the grade of dysplasia. This is one of the studies with the largest number of laryngeal EPL and invasive carcinoma studied sequentially. Our data confirm the role of some cell cycle regulatory proteins in the development of laryngeal carcinoma. Cytoplasmic retention of β-catenin in EPL seems to be related with more aggressive biological behavior. Combined increased p53 and cytoplasmic β-catenin protein expression could be biologically important in laryngeal tumorigenesis. Further research is required to clarify the involvement of β-catenin in the mechanism associated with malignant transformation in laryngeal tissues.