Objective: To evaluate cyclin D1 overexpression in oral squamous cell carcinomas and adjacent non-tumour epithelium as a biomarker of premalignant fields and a risk factor for multiple tumour development.
Design: We studied cyclin D1 expression in 54 patients with 68 oral squamous cell carcinomas plus adjacent non-tumour epithelia characterized as close (n = 58) or distant (n = 41) from the invasion point. Randomized 40x fields were evaluated (4 in tumour tissue and 1 each in close and distant non-tumour epithelium). Expression in non-tumour epithelium was evaluated in basal, parabasal, middle-third and upper-third compartments.
Results: Cyclin D1 overexpression was found in both carcinomas and non-tumour epithelia. Nuclear expression in basal and parabasal layers of distant epithelium was significantly increased in patients with multiple tumours (p < 0.001). A significant association between cyclin D1 overexpression in different epithelial layers was found in both close and distant epithelia. A significant association was found between nuclear expressions of cyclin D1 and Ki-67 in the basal layer of distant epithelium (p = 0.02).
Conclusions: Cyclin D1 overexpression is an early event in oral carcinogenesis linked to loss of the physiological asymmetrical proliferation pattern. Cyclin D1 overexpression in basal and parabasal layers of epithelia distant from the invasion point may act as a potential marker of premalignant fields and multiple tumour development.
Keywords: CCND1; Cyclin D1; Oral cancer; Premalignant fields.
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