BACKGROUND: Breast cancers shed cancer cells into the blood soon after they
become invasive. We developed an assay for removing these circulating canc
er cells. In this study, we wanted to determine the percentage of early sta
ge and metastatic patients with circulating breast cancer cells.
METHODS: Twenty milliliters of blood were drawn from patients with breast c
ancer. Epithelial cells were removed by immunomagnetic selection and analyz
ed by flow cytometry, cytomorphology, and immunocystochemistry.
RESULTS: Early stage patients averaged 16 epithelial cells per 20 cc blood
whereas metastatic patients averaged 122 tumor cells. Cytomorphology and im
munostains confirmed that these were cancer cells. Control blood samples ha
d 1.7 squamous epithelial cells per 20 cc blood.
CONCLUSION: This assay can identify and characterize circulating breast can
cer cells. Metastatic patients had more circulating cells than early stage
patients. This assay could screen high-risk patients, determine the need fo
r and monitor response to adjuvant therapy, and detect early recurrence of
breast cancer. (C) 2001 by Excerpta Medica, Inc.