| Research Abstract |
Interactions of cyclins, cyclin-dependent kinases (cdks) and tumor suppressor gene products are essential in cell cycle progression, and deranged expression of these factors are reported to evoke malignant transformation of the cell. To elucidate the tumorigenetic process of the endometrial carcinomas, expression of the cell cycle related molecules in normal and malignant endometrial tissues was investigated by immunostaining. In the normal endometrium, expression of cyclin A, cyclin B1, cyclin E, cdc2, cdk2 and p16 was sporadically observed in the glandular epithelia of the proliferative phase. In 64 cases of endometrial carcinomas, the number of positive cases for cyclin A, cyclin B1, cyclin D1, cyclin E, cdc2, cdk2, cdk4, p53, P16 and RB was 11, 32, 22, 41, 43, 32, 8, 22, 39, and 32 cases, respectively. The topographical distribution of cyclin D1, cyclin A and p53 positive cells correlated each other. Above 64 cases were classified into two groups. The first group was consisted of the cases showing positive for only cyclin E, and the second group was consisted of those expressing cyclin D1, p53 and cyclin A. The first group tended to contain well differentiated cases, and poorly differentiated cases were more frequently found in the second group. These findings suggest that accumulations of abnormalities of the cell cycle related factors are involved in the acquisition of the malignant potential of the endometrial carcinomas.
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