Detection of cytokeratin 19, human mammaglobin, and carcinoembryonic antigen-positive circulating tumor cells by three-marker reverse transcription-PCR assay and its relation to clinical outcome in early breast cancer.

Aims: To investigate the diagnostic, predictive, and prognostic value of the detection of circulating tumor cells (CTCs) using a three-marker (CK19, hMAM and CEA) RT-PCR assay in patients with early breast cancer. Patients and methods: Peripheral blood was obtained from 50 patients with early-stage breast cancer before any systemic adjuvant therapy and analyzed for the presence of CK-19, hMAM and CEA mRNA-positive CTCs using an RT-PCR assay. The specificity of the primers used was evaluated in 20 healthy individuals, 24 patients with benign breast disease, and 30 patients with metastatic breast cancer. The detection of CTCs was correlated with clinical outcome. Results: The detection rate of three-marker-positive CTCs in the blood of patients with early breast cancer was 54.0%, significantly higher than in patients with benign breast disease and healthy blood donors (p=0.002 and p=0.000, respectively). The three-marker RT-PCR assay had 58.8% sensitivity in the parallel test and 100% specificity for CTC detection in the serial test, which was higher than the sensitivity and specificity of single-marker assays. For early breast cancer, correlation analysis between detection of three-marker-positive CTCs and clinicopathological characteristics indicated that detection of three-marker-positive CTCs was significantly correlated with elevated serum CEA levels (p=0.001). After three years of follow-up, 13 of the 27 patients with three-marker-positive CTCs in their blood had relapsed and detection of three-marker-positive CTCs was significantly associated with locoregional recurrence and/or distant metastasis (p=0.002). Detection of three-marker-positive CTCs in peripheral blood was an independent risk factor for reduced median relapse-free interval (p=0.000). Conclusion: The three-marker RT-PCR assay can enhance the sensitivity and specificity of CTC detection compared to single-marker assay. Detection of three-marker-positive CTCs was associated with relapse and might have important predictive and prognostic implications in early breast cancer.