Apoptosis in normal epithelium, premalignant and malignant lesions of the oropharynx and oral cavity: a preliminary study

Abstract

To explore the involvement of apoptosis in the development of oral and oropharyngeal squamous cell carcinoma (SCC) in vivo, biopsies were taken from patients with macroscopically normal (n = 6), leukoplakic (n= 12) or malignant (n = 8) mucosa. Leukoplakic lesions were divided histologically into dysplasia (n=5) or carcinoma in situ (CIS: n=7). Material was prepared for light and electron microscopy. The apoptotic index (AI), vertical cell position of apoptoses (cp), mitotic index (MI) and AI:MI ratio were calculated for each patient. AI increased from 0.12% ± 0.07 S.E.M. (normal) to 0.58 ± 0.13 (CIS) but fell to 0.14 ± 0.14 in SCC. Apoptoses were suprabasal in normals, but generalised in CIS. MI increased from normal (0.20 ± 0.06) to SCC (0.32 ± 0.09), and AI:MI was at its maximum in CIS (1.57; SCC: 0.44). The results suggest that a change in apoptosis accompanies the onset of invasion in a premalignant lesion of the human oral cavity and oropharynx.