目的　探讨端粒酶基因与乳腺导管不典型增生恶性转化的关系及其作用。方法　应用原位杂交方法检测端粒酶基因hTR和hTRT在 5 0例乳腺导管增生组织 (其中单纯性增生 6例 ,轻度不典型增生 9例 ,中度不典型增生 12例、重度不典型增生 2 3例 )及 2 6例乳腺癌中的表达。结果　在乳腺导管单纯性增生组织中hTR、hTRTmRNA呈弱表达 (1/6 )和阴性。在乳腺导管轻、中度不典型增生组织中hTR、hTRTmRNA呈弱表达 (2 /9、1/9;4 /12、3/12 ) ,在乳腺导管重度不典型增生组织中hTR、hTRTmRNA表达增强 (14 /2 3,6 0 9% ,12 /2 3,5 2 1% ) ,在乳腺癌组织中端粒酶基因hTR、hTRTmRNA呈较强阳性表达 (2 3/2 6 ,88 5 % ;2 1/2 5 ,80 8% )。乳腺导管重度不典型增生组织中的端粒酶基因表达与在轻、中度不典型增生、浸润性导管癌组织中的表达比较差异有显著性意义 (P <0 0 5 ) ,但与导管内癌表达差异无显著性意义 (P >0 0 5 )。结论　端粒酶基因hTR、hTRT的表达与乳腺导管不典型增生细胞的恶性转化密切相关 ,端粒酶的重新激活可能在乳腺癌的组织发生中起关键性作用 Objective To investigate the relationship between the telomerase gene and the atypical hyperplasia and malignant transformation of breast duct. Methods In situ hybridization was used to detect hTR and hTRT in 50 cases of ductal hyperplasia (including 6 cases of simple hyperplasia, 9 cases of mild dysplasia, 12 cases of moderate dysplasia and severe dysplasia 23 cases) and 26 cases of breast cancer expression. Results hTR and hTRT mRNA were weakly expressed (1/6) and negative in simple ductal hyperplasia of mammary duct. HTR and hTRTmRNA were weakly expressed in mild and moderately dysplastic breast duct tissues (2 / 9,1 / 9; 4 / 12,3 / 12). The expression of hTR and hTRTmRNA was enhanced in severe ductal atypical hyperplasia The expression of hTR mRNA and hTRT mRNA in breast cancer tissues was strongly positive (2 3/2 6, 88 5%; 2 1/2 5, 80 8%). The expression of telomerase gene in severe atypical hyperplasia of mammary duct was significantly different from that in mild and moderate dysplasia and invasive ductal carcinoma (P <0 05) There was no significant difference in the expression of cancer (P> 0.05). Conclusion The expression of hTR and hTRT in telomerase gene is closely related to the malignant transformation of atypical hyperplasia ductal cells. The reactivation of telomerase may play a key role in the carcinogenesis of breast cancer