Open AccessTumor dissemination to distant organ is the main cause of death. Therefore there is urgent need to set up sensitive methods for early detection of circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) in peripheral blood (PB) and bone marrow (BM) specimens of breast cancer patients. We aim to detect MUC2 mRNA positive cells in PB and BM of breast cancer patients; to relate this to patient relapse. In this study to detect MUC2 mRNA positive cells (tumor marker), PB and BM samples were collected from 50 breast cancer patients after operation and before adjuvant therapy with 20 PB from healthy individuals as negative controls. Chi-square test was used to analyze data. MUC2 mRNA by using Real-time PCR was detected in 9 (18%) of PB and in 10 (20%) of BM samples and none of the healthy individuals. The relapse rate among MUC2-positive patients was significance in BM (P < 0.004) and MUC2-positive patients had a shorter disease free survival than the negative patients in BM samples (p < 0.05). This study shows MUC2 can be a suitable marker for detection of micrometastasis in breast cancer patients at early stages of cancer.