Expression of Cyclin A and Ki-67 in the Uterine Cervical Carcinoma

Kim, Min Kwan; Bae, Dong Han; Kim, Chang Jin

Abstract

The cell cycle is the set of events that is responsible for the duplication of the cells. Recent studies indicate that cell cycle regulatory proteins, mainly the cyclins and cyclin-related genes, can be critical targets during oncogenesis. The genes and gene products normally control specific events in the cell cycles, particularly during the late G1 and early S phase and G2/M phase. A large body of date implicates cyclins in oncogenesis. The first evidence came from human cyclin A in oncogenesis. Cyclin A is expressed from the late G1 phase through the M-phase of the cell cycle. Cyclin A is known as positive regulator of cell cycle and participates in the tumorigenesis. Overexpression of cyclin A has been reported in several cancers. Ki-67 is a nuclear protein expressed during the cell cycle except in Go. The labeling index of Ki-67 in the tumor cell nuclei has been used as a good prognostic factor. In this study, we compared labeling index of cyclin A and Ki-67 to assess the feasibility between them with 30 cases of cervical intraepithelial neoplasia(CIN) and 20 cases of invasive squamous cell carcinoma(SCC)by immunohistochemistry. The results were as follow; 1. Cyclin A expressed in normal parabasal cells and their labeling index was 0.8+/-0.4%, while in CIN and invasive SCC 65.5+/-9.4% and 86.5+/-12.3% respectively. Ki-67 expressed in normal parabasal cells as 1.3+/-0.7% while in CIN and invasive SCC as 77.8+/-12.9% and 92.2+/-17.6% respectively. 2. In CIN, the expression of cyclin A increased according to the grades of the CIN as 32.5+/-5.7%, 75.8+/-9.0%, and 83.2+/-13.4% in CIN I, II and III respectively. The expression of the Ki-67 also increased according to the grades of the CIN as 51.8+/-9.8%, 87.9+/-11.3%, and 93.6+/-17.5% respectively in CIN I, II and III. 3. There was no differences of cyclin A and Ki-67 expressions according to the histologic types of invasive SCC. Above results suggests that the cyclin A labeling index could be used as a marker of tumor progression in the uterine cervical carcinoma as Ki-67.