Combination of immunomagnetic enrichment with multiplex RT-PCR analysis for the detection of disseminated tumor cells.

A highly specific and sensitive tumor cell detection assay is reported, which combines immunomagnetic enrichment with multiplex RT-PCR analysis. 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. 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. 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.