aCenter for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114;
bShriners Hospital for Children, Harvard Medical School, Boston, MA 02114;
cDepartment of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114;
dMassachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114;
eDepartment of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114;
gDepartment of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114; and
fHoward Hughes Medical Institute, Chevy Chase, MD 20815
↵3Present address: Division of Medical Engineering Research, National Health Research Institutes, No. 35, Keyan Road, Zhunan Town, Miaoli County, 35053, Taiwan.
Contributed by Kurt J. Isselbacher, August 24, 2010 (sent for review July 14, 2010)
↵1S.L.S. and C-H.H. contributed equally to this work.
Rare circulating tumor cells (CTCs) present in the bloodstream of patients with cancer provide a potentially accessible source for detection, characterization, and monitoring of nonhematological cancers. We previously demonstrated the effectiveness of a microfluidic device, the CTC-Chip, in capturing these epithelial cell adhesion molecule (EpCAM)-expressing cells using antibody-coated microposts. Here, we describe a high-throughput microfluidic mixing device, the herringbone-chip, or “HB-Chip,” which provides an enhanced platform for CTC isolation. The HB-Chip design applies passive mixing of blood cells through the generation of microvortices to significantly increase the number of interactions between target CTCs and the antibody-coated chip surface. Efficient cell capture was validated using defined numbers of cancer cells spiked into control blood, and clinical utility was demonstrated in specimens from patients with prostate cancer. CTCs were detected in 14 of 15 (93%) patients with metastatic disease (median = 63 CTCs/mL, mean = 386 ± 238 CTCs/mL), and the tumor-specific TMPRSS2-ERG translocation was readily identified following RNA isolation and RT-PCR analysis. The use of transparent materials allowed for imaging of the captured CTCs using standard clinical histopathological stains, in addition to immunofluorescence-conjugated antibodies. In a subset of patient samples, the low shear design of the HB-Chip revealed microclusters of CTCs, previously unappreciated tumor cell aggregates that may contribute to the hematogenous dissemination of cancer.