Apoptosis and cell proliferation in esophageal precancerous and cancerous lesions: study of a high-risk population in northern China.

Changes in cell proliferation and cell death might be key factors in regulating the rate of neoplasm progression and tumor growth. The extent of apoptosis and its possible relationship with cell proliferation at different stages of esophageal carcinogenesis, however, have not been characterized. In this study, 241 esophageal biopsy samples from symptom-free subjects and 38 surgically resected esophageal carcinoma tissues from a high-risk population for esophageal cancer in Henan, China, were used to analyze the changes of apoptosis and its relationship with cell proliferation as determined by proliferating cell nuclear antigen (PCNA). The apoptotic cells, identified morphologically, were located in the same proliferative compartment of hyperproliferative cell population in the esophageal epithelium. The apoptotic indices (total number of apoptotic cells and apoptotic bodies per mm2 of the tissue section) were low in the normal epithelia, and increased significantly as the lesions progressed from basal cell hyperplasia (BCH) to dysplasia (DYS) and to squamous cell carcinoma (SCC). The extent of apoptosis correlated well with the cell proliferation indices. The present findings indicate that apoptosis occurs in the early stage of esophageal carcinogenesis, and as the lesions progress, both the apoptotic index and PCNA labelled index increase, suggesting that hyperproliferative cells might be more susceptible to apoptosis.