Journal of Pathology and Translational Medicine

Original Articles

Telomerase Activity and Expression of Telomerase RNA in Malignant Fibrous Histiocytoma.: Jinyoung Yoo, Seok Jin Kang, Bung Kee Kim; Korean J Pathol. 2000;34(8):581-587.

Abstract PDF: Telomerase is an RNA-dependent DNA polymerase that synthesizes TTAGGG telomeric DNA onto chromosomal ends to compensate for sequence loss during replication. It has been detected in a variety of human malignancies, suggesting that such activity may play a role in the tumorigenic process. To determine whether telomerase is reactivated in malignant fibrous histiocytoma, 12 tissue samples with this tumor were analyzed for the telomerase activity by a radioactive PCR-based TRAP (telomeric repeat amplification protocol) assay. All of the tumors were further investigated for the expression of human telomerase RNA (hTR) by an in situ hybridization (ISH). Telomerase activity was detected in one (8.3%) sample. Expression of hTR was demonstrated in 7 (58.3%): one telomerase-positive and six telomerase-negatives. These data indicate that the reactivation of telomerase is an uncommon event and not an important factor involved in tumorigenesis in malignant fibrous histiocytoma. It is noteworthy that 50% of the patients with grade 2 tumors expressed hTR, suggesting that telomerase RNA may be useful as a marker for identifying tumor aggressiveness earlier than the conventional histopathologic grading scale.

Telomerase Activity and Expression of MIB-1 and bcl-2 in Human Chorionic Villi from Early and Term Normal Pregnancy.: Jung Sook Cho, Young Soon Kang, In Gul Moon, Bum Chae Choi, Jong Pyo Lee, Hoon Taek Lee, Sung Ran Hong; Korean J Pathol. 2000;34(11):927-933.

Abstract PDF: Telomerase is an enzyme that maintains telomeres and prevents telomere shortening, and may be linked with cellular proliferation or the aging process. The purpose was to examine telomerase activity in human chorionic villi from early and term normal pregnancies, and to analyze the correlation of telomerase activity (TA) with MIB-1 & bcl-2. A total of 37 placentae were obtained from 16 early and 21 term pregnancies. TA was assayed by telomeric repeat amplification protocol, and immunohistochemical staining was performed for MIB-1 & bcl-2 expression. TA & MIB-1 expression were strong in early placenta, but bcl-2 was highly expressed in term placentae. Thirteen (81.25%) of 16 early placentae showed TA, but only 2 (9.52%) of 21 term placentae expressed TA (p<0.01). MIB-1 was observed in nuclei of cytotrophoblast, and the expression rate was 16.09% in early placentae and 2.87% in term placentae (p<0.01). bcl-2 was observed only in the cytoplasm of syncytiotrophoblast. Term placenta demonstrated stronger expression of bcl-2 compared to early placentae (p<0.05). These findings suggest that TA, MIB-1 & bcl-2 expression are critically regulated over the course of gestation: cytotrophoblast, main cells of early chorionic villi, may be a common source of telomerase and proliferative activity. The TA showed good correlation with cellular proliferative activity. Syncytiotrophoblast, may be a main source of bcl-2 expression which is stronger in the term placentae.

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