目的　检测原发性乳腺癌骨髓微转移的发生及与其它临床参考指标的关系。方法　应用逆转录 -聚合酶链反应 (RT -PCR)并Southern杂交技术 ,检测骨髓单个核细胞中细胞角蛋白 19(CK - 19)基因表达。结果　 5 2例骨髓标本共检出微转移 19例 ( 3 6.5 % ) ,其中 17例淋巴结有转移者 ,9例CK - 19表达阳性 ( 5 2 .9% ) ;而无淋巴结转移的 3 5例中 ,10例CK - 19表达阳性 ( 2 8.6% )。微转移检出率与肿瘤大小有关 (P <0 .0 5 )。结论　以CK -19为标志物 ,RT -PCR并Southern杂交方法检测原发性乳腺癌骨髓微转移灵敏、特异 ,可做为临床判断预后的参考指标。 Objective To detect the occurrence of bone marrow micrometastasis in primary breast cancer and its relationship with other clinical reference indexes. Methods Reverse transcription polymerase chain reaction (RT-PCR) and Southern blotting were used to detect the expression of cytokeratin 19 (CK-19) in bone marrow mononuclear cells. Results A total of 19 cases (36.5%) of micrometastasis were detected in 52 bone marrow specimens, of which 17 cases had lymph node metastasis, 9 cases were positive for CK-19 (52.9%), and 35 cases without lymph node metastasis. In 10 cases, CK-19 expression was positive (2.6%). The detection rate of micrometastasis was related to tumor size (P < 0.05). Conclusion The CK-19 as a marker, RT-PCR and Southern blotting method are sensitive and specific for the detection of bone marrow micrometastasis in primary breast cancer. It can be used as a reference index for clinical judgment of prognosis.