Objective: Despite the advances in treatment, breast cancer (BC) remains a major cause of death in women. Thisstudy aims to evaluate the prognostic significance of detecting circulating tumor cells (CTCs) and disseminated tumorcells (DTCs) in paired peripheral blood (PB) and bone marrow (BM) samples obtained both before and after adjuvantchemotherapy from patients with operable BC.Materials and Methods: In this experimental study, from 160 patients with primary BC, we collected 160 PB and BM samplesbefore and we could be able to collect PB and BM samples from 100 of them after adjuvant chemotherapy. The expressionlevel of cytokeratin 19 (CK19), carcinoembryonic antigen (CEA), mammaglobin 1 (MGB1), mucin 2 (MUC2) and trefoil factor1 (TFF1) mRNAs in the PB/BM samples were analyzed by quantitative real-time polymerase chain reaction (PCR).Results: Multivariate Cox regression analyses indicated that the detection of CK19 mRNA-positive CTCs/DTCs eitherbefore or after adjuvant chemotherapy was an independent factor for prognosis associated with decreased diseasefreesurvival (DFS). Patients with tumor cells detected in both PB and BM and patients with persistent detection oftumor cells before and after chemotherapy had worse outcomes compared to those with tumor cells detected in one orneither of the compartments.Conclusion: This study suggests that the detection of CK19 mRNA-positive CTCs/DTCs either before or after adjuvantchemotherapy could be an independent predictor of DFS in operable BC patients.
