Asymmetrical proliferative pattern loss linked to cyclin D1 overexpression during malignant transformation of the lip epithelium.

ABSTRACT

BACKGROUND: There is inadequate knowledge on the involvement of oncogenic mechanisms linked to the cyclin (CCND1) gene in lip squamous cell carcinoma (LSCC). OBJECTIVE: The aim of this study was to analyse the implication of cyclin D1 in the malignant transformation of lip lesions. METHODS: We immunohistochemically studied 45 actinic cheilitis cases (15 mild dysplasia, 15 moderate dysplasia, 15 severe dysplasia/carcinoma in situ), 30 LSCC cases with adjacent non-tumour epithelium and 15 normal oral epithelium samples for detection of cyclin D1, ß-catenin and Ki-67. RESULTS: Cyclin D1 and Ki-67 expressions were significantly increased in the basal layer of premalignant epithelia and peripheral layers of tumour nests vs. CONTROLS Premalignant epithelia had lost their asymmetrical proliferative pattern. CONCLUSION: Lip carcinogenesis was associated with loss of the asymmetrical proliferative pattern, a preventive mechanism against lip oncogenesis, and with cyclin D1 overexpression.