Combining Mammaglobin and Carcinoembryonic mRNA Markers for Early Detection of Micrometastases from Breast Cancers - a Molecular Study of 59 Patients

Introduction: As many as 30% of node-negative breast cancer patients relapse within five years, suggesting thatcurrent histological detection methods are inadequate for identifying metastatic disease. Detecting small number ofcancer cells in the breast tissue or lymph node by reverse transcription-polymerase chain reaction (RT-PCR) assaysusing a combination of tissue and cancer specific markers might be very useful in the early detection or monitoringof the treatment. Mammaglobin is a member of the uteroglobin gene family and appears to be expressed only inbreast tissue. Carcinoembryonic antigen has been the preferred molecular marker for detection of micro metastasesin lymph nodes in almost all carcinomas. Materials and
Methods: Samples were collected from randomly chosenbreast cancer patients undergoing modified mastectomy or breast conserving surgery between September 2003 andJuly 2004. RT-PCR was applied to study the expression of MMG and CEA markers. Breast cancer micrometastasesin axillary lymph nodes were also assessed.
Results: The MMG marker was positive in 9/10 normal breast tissues, 3/3 breast fibroadenomas and 37/39 of breast carcinoma tissues, giving an overall sensitivity of 94%. The sensitivitywas 80% for metastatic lymph node samples. On the other hand CEA showed 95% sensitivity for malignant breasttumors and 100% sensitivity for metastatic lymph nodes.
Conclusions: RT-PCR using a combination of MMG andCEA markers is a powerful tool to complement current routine histopathology techniques for detection of breastcancer metastasis in axillary nodes.