Aim: Patients with breast cancer should have a favorable outcome when diagnosed early. Occult distant metastases, 
especially in the Bone Marrow (BM) was claimed to be responsible for tumor relapse in certain cases, especially in 
HER-2/neu expressing tumors. Such an occult metastases may be detected by PCR techniques for a BM aspirate, which is the aim of this study. 
Methods: Between May 2004 and May 2005, PCR technique was used to determine the tumor HER-2/neu status of 37 
patients, attending Suez Canal University Hospital for the treatment of stage I-III breast cancer. BM and peripheral blood of those positive patients were examined by the same technique for the presence of micro-metastases. Correlation between tumor characteristics and the HER-2/neu status was done. 
Results: Fifteen patients were tumor HER-2/neu positive, which correlated with stage and number of positive lymph nodes. BM micro-metastases were detected in 7 patients, with no correlation to the tumor characteristics. Additionally, HER-2/neu positive tumor cells were detected in the peripheral blood of 6 patients. 
Conclusion: BM micro-metastases can be detected in HER-2/neu positive non-metastatic breast cancer that may be predicted by the peripheral blood not the primary tumor characteristics