Bmi-1 及Mel-18在乳腺癌中的表达及其与临床病理特征的关系

目的：探讨Bmi-1和Mel-18在乳腺癌组织中的表达和临床意义。方法：采用RT-PCR和免疫组织化学染色法检测Bmi-1和Mel-18基因与蛋白在40例乳腺癌组织和20例乳腺良性肿瘤组织及20例正常乳腺组织中的表达。分析两者在乳腺癌组织中的表达情况和相关性，以及两者表达与临床病理因素的关系。结果：Bmi-1 mRNA的表达和蛋白阳性率在正常乳腺组织、乳腺良性组织、乳腺癌组织均呈明显依次递增（均P<0.05），而Mel-18则基本呈反向趋势（正常乳腺组织与乳腺良性组织间差异不明显）；乳腺癌组织中Bmi-1与Mel-18 mRNA及蛋白表达之间均明显呈负相关（r=-0.317，P=0.023；r=-0.413，P=0.008）；两者基因表达和蛋白阳性率水平与淋巴结转移及临床分期密切相关（均P<0.05），而与患者的年龄、绝经状况、肿瘤大小、组织学分级无关（均P>0.05）。结论：Bmi-1过表达与Mel-18低表达可能是乳腺组织恶性转变以及乳腺癌发生浸润转移的重要生物学标志。

Clinicopathological study of Bmi-1 and Mel-18 expression in breast cancer

Objective: To investigate the expression of Bmi-1 and Mel-18 in breast cancer tissue and their clinical significance. Methods: The gene and protein expression in malignant (40 cases), benign (20 cases) and normal (20 cases) breast tissues were determined by RT-PCR and immunohistochemical method, respectively. The Bmi-1 and Mel-18 expression status and their correlationship in breast cancer tissue, and the relations of their expressions with the clinicopathologic factors were analyzed. Results: Both mRNA and protein positive expression of Bmi-1 increased significantly and successively in normal, benign and malignant breast tissues (all P<0.05), while those of the Mel-18 showed a roughly opposite tendency (no significant difference between normal breast tissue and benign breast lesion). There was a significant negative correlation between Bmi-1 and Mel-18 expression at either mRNA or protein level in breast cancer tissue (r=–0.317, P=0.023 and r=–0.413, P=0.008). The mRNA and protein levels of both Bmi-1 and Mel-18 were significantly related to the lymph node metastasis and clinical stage (all P<0.05), but not associated with the age, menstrual status, tumor size and histologic classification of the patients (all P>0.05). Conclusion: The increased Bmi-1 expression along with decreased Mel-18 expression may probably be important biological markers for malignant transformation of breast tissue or invasion and metastasis of breast cancer.