DNA content and PCNA immunoreactivity in oral precancerous and cancerous lesions.

Thirty-three dysplastic lesions showing varying degrees of atypia located in the oral cavity and 83 squamous cell carcinomas located in the oral cavity and tongue (n = 56) or in the lips (n = 27) were analysed by means of proliferating cell nuclear antigen (PCNA) immunoreactivity and image cytometric DNA measurements. The results show that in dysplastic lesions increasing cellular atypia correlated to elevated proliferative activity and aneuploidy occurring in the basal cell layers. In highly differentiated squamous carcinomas increased PCNA immunoreactivity and aneuploidy was preferentially observed focally (grade 1 tumours) or in the invasive zones (grade 2 tumours). In contrast, more poorly differentiated carcinomas (grade 3 and 4 tumours) showed strongly elevated proliferative activity and aneuploidy throughout the entire tumour mass.