Telomerase Activities in Ovarian Malignancies

Song, J H; Cho, C H; Cha, S D; Lee, T S

Abstract

Telomerase is a ribonucleoprotein that can add hexameric TTAGGG sequences to the end of chromosomes and thus stabilize telomeres. Telomeres are shortened by progression of cell division, a process known as cellular senescence. If telomerase activity is not activated the chromosomes are shortened to a critical length and the division of cell is stopped. In cancer cells telomere shortening is stopped by the prescence of the enzyme telomerase and the cells divisions is contined indefinitely. Most normal somatic tissues don`t express telomerase activity, but both fetal and adult human ovaries and testis express telomerase. To investigate the relationship between telomerase activity and acquisition of malignancy in ovaries, the activity of telomerase was assayed in normal, benign, borderline and malignant ovarian tissues. With TRAP assay, the telomerase activity was examined in 15 normal ovarian tissues, 1 benign mucinous cystadenoma, 1 borderline carcinoma, and 10 ovarian malignancies. Telomerase activities were detected weakly in 9 of 15 cases of normal ovarian tissues and were not related to the activity of reproduction. The strong activity of telomerase were found in borderline carcinoma and 5 of 6 cases of epithelial ovarian carcinoma and 1 rest case revealed low activity. Telomerase activities in dysgerminoma were undetectable in one and weak in rest one, but 1 case of immature teratoma revealed strong activity. The telomerase is reactivated or upregulated in epithelial carcinoma of the ovary, as it is detectable in borderline carcinoma, but is undetectable or weakly detectable in benign ovarian tumor and normal ovarian tissues. Telomerase activity is closely related to the epithelial ovarian carcinoma, and it may be useful as a marker for diagnosis and as a target for therapeutic intervention. The dysgerminoma revealed no or weak activity of telomerase compared to another germ cell tumors and epithelial carcinomas, so further study will be needed to examine the role of telomerase activity in dysgerminoma.