An ultrasensitive tumor enriched flow-cytometric assay for detection of isolated tumor cells in bone marrow of patients with breast cancer

Abstract

Background: An ultrasensitive tumor enriched flow-cytometric assay was used to determine its feasibility in detection of isolated tumor cells (ITC) in bone marrow (BM) of patients with breast cancer.

Methods: Epithelial cells were removed by magnetic microbeads conjugated with an anti-cytokeratin 7/8 monoclonal antibody to enrich tumor cells in BM samples. A specific gate for MCF-7 breast cancer cells (gate(MCF-7 cells)) was also taken into consideration in addition to a gate including all enriched BM cells (gate(enriched BM cells)) in flow-cytometric analysis to enhance the specificity of the method.

Results: Nineteen patients with stage I/II were evaluated. Ten patients (53%) were found to have cytokeratin positive (CK(+)) cells according to the gate(enriched BM cells) whereas 6 patients (32%) had CK(+) cells when the gate(MCF-7 cells) was taken into account.

Conclusions: New strategies in nonmorphological ultrasensitive techniques might be useful to categorize patients with ITCs having different tumor morphology and characteristics.