Expression of telomerase genes in cancer development in atypical hyperplasia of the mammary duct.

OBJECTIVE: To investigate telomerase gene expression in precancerous mammary lesion, such as atypical ductal hyperplasia and breast cancer and to study the relationship between expression and malignant transformation. METHODS: Expression of human telomerase genes (hTR) and human reverse transcriptase gene (hTRT) in 76 cases of mammary tissue was evaluated using in situ hybridization and included 50 cases of mammary hyperplasia, 6 of which were benign hyperplasia, 9 were mild atypical hyperplasia, 12 were moderate atypical hyperplasia, 23 were severe atypical hyperplasia and 26 were mammary cancer. RESULTS: The expressions of hTR and hTRT mRNA were much weaker or negative in benign hyperplasia (16.6%, 0), weak to mild moderate in atypical hyperplasia (22.2%, 11.1%, 33.3%, 25.0%), strong in severe atypical hyperplasia (60.9%, 52.1%), and significantly strong in mammary cancer (88.5%, 80.8%). The difference between mild-moderate atypical hyperplasia, invasive ductal carcinoma and severe atypical hyperplasia was significant (P < 0.05) and the difference between severe atypical hyperplasia and intraductal carcinoma was not significant (P > 0.05). CONCLUSION: Telomerase genes (hTR and hTRT) expressions are related to the transformation of atypical hyperplasia. Activated telomerase may play a role in mammary cancer development.

[Expression of telomerase genes in mamary atypical ductal hyperplasia].

OBJECTIVE: To investigate the relationship of telomerase genes and the malignant transformation of atypical mammary ductal hyperplasia. METHODS: Telomerase genes hTR and hTRT in 50 cases of mammary hyperplasia (the cases included 6 benign hyperplasia, 9 mild atypical hyperplasia, 12 medium atypical hyperplasia, 23 severe atypical hyperplasia) and 26 cases of breast carcinoma were detected by in situ hybridization. RESULTS: The expression of hTR and hTRT mRNA were weak or negative in benign hyperplasia (1/6, 0), weaker in mild-moderate atypical hyperplasia (2/9, 1/9, 4/12, and 3/12), strong in severe atypical hyperplasia (14/23, 60.9% and 12/23, 52.1%), while very strong expression (23/26, 88.5% and 21/25, 80.8%) in carcinoma of the breast. The difference between mild-moderate atypical hyperplasia, invasive ductal carcinoma and severe atypical hyperplasia was significant (P < 0.05) and the difference between severe atypital hyperplasia and intraductal carcinoma was not significant (P > 0.05). CONCLUSIONS: Telmerase genes (hTR, hTRT) expression is closely related to the malignant transformation of atypical hyperplasia. The reactivated telomerase may play a crucial role in the development of breast cancer.

[Relationship between expressions of telomerase genes and apoptosis related genes in mammary ductal atypical hyperplasia].

BACKGROUND & OBJECTIVE: Recent studies showed that the activating of telomerase and excessive expression of apoptosis suppressor genes were related to the development of many tumors. This study was designed to investigate the expression of telomerase genes (hTR, hTRT) and apoptosis related genes (p53, bcl-2) in mammary atypical ductal hyperplasia for exploring the change of telomerase activity and apoptosis related genes in the process of mammary ductal dysplasia to malignant transformation. METHOD: Expressions of telomerase genes (hTR, hTRT) and apoptosis related genes (p53, bcl-2) were detected by in situ hybridization and expression of the mutant p53 protein was detected by immunohistochemistry were detected in 44 patients with mammary atypical ductal hyperplasia, those expression were compared with those of the 6 benign hyperplasia and 26 breast carcinoma. RESULT: High expressions of telomerase genes (hTR, hTRT mRNA) in severe atypical ductal hyperplasia (60.9%, 52.1%) is of significantly difference from that in mild-medium atypical ductal hyperplasia (22.2%, 11.1%; 33.3%, 25.0%) and breast cancer (88.5%, 80.8%). The upgrading of atypia link with decreased expression of wild p53 mRNA (mild: 55.6%; medium: 41.7%; severe: 26.1%) and increased expression of the mutant p53 protein (mild: 11.1%; medium: 25.0%; severe: 34.8%). As for bcl-2 mRNA, it shows moderate expression, especially in severe atypical ductal hyperplasia. CONCLUSION: Our study revealed significant correlation between expressions of telomerase genes (hTR, hTRT) and the state of malignant transformation in mammary atypical ductal hyperplasia. Decreased expression of wild p53 gene, increased expression of mutant p53 protein, and overexpression of bcl-2 gene were associated with telomerase.