Combination of Immunomagnetic Enrichment with Multiplex RT-PCR Analysis for the Detection of Disseminated Tumor Cells

Background: A highly specific and sensitive tumor cell detection assay is reported, which combines immunomagnetic enrichment with multiplex RT-PCR analysis. Materials and Methods: The effect on the recovery rate of breast, testicular and colorectal cancer cells using single antibodies and combinations of them for IMS was examined by fluorescence microscopy and multiplex RT-PCR. The clinical utility of a tumor cell detection assay using IMS with multiplex RT-PCR was tested by examination of colorectal cancer blood samples and by comparing the results with CEA serum protein levels. Results: A combination of antibodies for IMS and multiplex RT-PCR analysis proved to be the most sensitive approach for detection of tumor cells in peripheral blood with a detection limit of two tumor cells. The examination of blood of colorectal cancer patients by using a multiplex RT-PCR assay in comparison with CEA serum protein levels indicated a distinct advantage of the former over the latter with respect to a more reliable prediction of an ongoing metastatic process. Conclusion: The results indicate that a combination of antibodies for immunomagnetic enrichment with multiplex RT-PCR analysis detects disseminated tumor cells with high sensitivity and specificity, thus indicating a metastatic process several months earlier compared to CEA serum protein level measurements. This assay might be valuable for prognosis in cancer.