Abstract:Objective:To evaluate the clinical value of detection of circulating tumor cells of breast cancer by nested RT-PCR using combimation of cytokeratin 19(CK19)and small breast epithelial mucin(SBEM). Methods:The reverse transcripted products of the gradient mixture of the RNA of MCF-7 cells and peripheral mononuclear cells of healthy volunteers were detected by the optimized nested RT-PCR to evaluate its sensitivity. Peripheral blood of 10 healthy volunteers and 20 patients of benign lesions of breast were detected to evaluate its specificity,and peripheral blood of 56 patients of breast cancer were detected. Results:The optimized detecting system detected MCF-7 cell from peripheral mononuclear cells of 3 ml peripheral blood,and no positive expression of CK19 mRNA and SBEM mRNA were found in 10 healthy volunteers and 20 patients of benign lesions of breast. The expression of the two markers was related to the size of primary tumor,axillary lymph nodes status and TNM(P < 0.05),but not related to the status of ER,PR and C-erbB-2(P > 0.05). Conclusion:The optimized nested RT-PCR system achieved higher sensitivity and specificity,could detect the expression level of CK19 mRNA and SBEM mRNA effectively in the peripheral blood of breast cancer patients;CTC detection is useful for the assessment of prognosis and treatment of breast cancer patients.