Assay of Proliferative Activity, Clonality and Immortality of

Kim, Hyung Seok; Lee, Young Jik; Kim, Mee Sook; Ko, Hyang Mi; Juhng, Sang Woo

Abstract

Among the precancerous lesions, dysplasia of the uterine cervix and adenoma of the colon have been widely studied in terms of genetic alterations. However, little has been performed regarding phenotypic alterations of the precancerous lesions. We investigated the relationship among cellular proliferation, clonality, immortality and histopathologic grading of the squamous epithelial lesions of the uterine cervix. Proliferation index (PI) was calculated based on the ratio of the epithelial cells positive for proliferating cell nuclear antigen to the total epithelial cells. Clonality was assayed by X-linked HUMARA polymorphism. For immortality assay, PCR-based TRAP (telomeric repeat amplification protocol) was done and telomerase processivity was calculated by comparison with the positive control. PI increased gradually as the lesions advanced from dysplasia to invasive carcinoma. Among informative case, all of the carcinoma in situ showed monoclonal pattern (7 of 7). Among invasive squamous cell carcinoma, 6 cases showed monoclonal pattern and 2 cases polyclonal pattern. TRAP reaction was positive in 92.6% (25 of 27) of dysplasia (high grade: 14 of 15; low grade: 11 of 12), 95.0% (19 of 20) of carcinoma in situ, 100% (9 of 9) of microinvasive carcinoma, and 92.9% (13 of 14) of invasive carcinoma. It was also positive in 12 of 12 samples of chronic cervicitis or squamous metaplasia near the lesions of dysplasia. There was no difference in TRAP positivity among the dysplasia, carcinoma in situ and invasive carcinoma, whereas telomerase processivity showed significant correlation. These results suggest that proliferative activity and telomerase processivity may be progressive events in oncogenesis, although telomerase activation may be an early event.