Test for Occult Micrometastases in Primary Breast Cancer

We will develop and validate a new assay system to replace existing immunocytochemicalassays for detecting occult micrometastases in bone marrow of patients with primary breast cancer.This assay would offer simplicity, low cost, and a quantitative end point. The assay is based on aninnovative amplification mechanism, the bacterial chain reaction (BCR), which is potentially capable oflowering the detection limit to one micrometastasis in 10 million bone marrow cells. The BCR utilizesliving cells of an autosyntrophic strain of Escherichia coil to amplify signals from reporter molecules, e.g.,enzyme-labeled monoclonal antibodies. Under the BCR conditions, reporter molecules trigger nearbyautosyntrophic cells to initiate a proliferative chain reaction resulting in discrete visible bacterial coloniesclustered around tumor cells. Phase I will optimize the BCR assay and assess its detection limits of usinga model system. For Phase II, the BCR assay will be validated by applying it to detection andenumeration of occult micrometastases in bone marrow specimens from patients with primary breastcancer. The final objective is to produce a BCR assay kit to be marketed as a diagnostic tool in theclinic.