A negative selection system PowerMag for effective leukocyte depletion and enhanced detection of EpCAM positive and negative circulating tumor cells

Abstract

Background: Circulating tumor cells (CTCs) can be enriched from peripheral blood by leukocyte depletion. In this study, a PowerMag system was designed to enhance leukocyte depletion and CTC detection.

Methods: The efficiency of PowerMag in leukocyte depletion and recovery of CTCs was evaluated. The cell populations in leukocyte-depleted cell filtrate were characterized by immunofluorescence staining using anti-EpCAM and anti-CD45 antibodies. The suitability of PowerMag in monitoring cancer patient CTCs was assessed by analyzing blood samples collected at baseline and 2 weeks after baseline from the patients with colorectal cancer (CRC, n=24) and head and neck squamous cell carcinoma (HNSCC, n=28).

Results: Only few contaminated CD45(+)-leukocytes were retained in the leukocyte-depleted cell filtrate. The enriched CTCs were viable with a recovery rate of 46-62%. Immunofluorescence staining of the nucleated cells enriched by PowerMag revealed 2 major cell populations EpCAM(+)CD45(-) and EpCAM(-)CD45(-). The number for both cell types was significantly increased in cancer patients when compared to healthy control. After chemotherapy, the number of EpCAM(+)CD45(-) and EpCAM(-)CD45(-) cells was decreased more prominently for CRC and HNSCC patients, respectively.

Conclusions: PowerMag holds great promise as a platform for leukocyte depletion and CTC detection in a clinical setting.