NanoVelcro Chip for CTC enumeration in prostate cancer patients.

Circulating tumor cells (CTCs) are one of the most crucial topics in rare cell biology and have become the focus of a significant and emerging area of cancer research. While CTC enumeration is a valid biomarker in prostate cancer, the current FDA-approved CTC technology is unable to detect CTCs in a large portion of late stage prostate cancer patients. Here we introduce the NanoVelcro CTC Chip, a device composed of a patterned silicon nanowire substrate (SiNW) and an overlaid polydimethylsiloxane (PDMS) chaotic mixer. Validated by two institutions participating in the study, the NanoVelcro Chip assay exhibits very consistent efficiency in CTC-capture from patient samples. The utilized protocol can be easily replicated at different facilities. We demonstrate the clinical utility of the NanoVelcro Chip by performing serial enumerations of CTCs in prostate cancer patients after undergoing systemic therapy. Changes in CTC numbers after 4-10 weeks of therapy were compared with their clinical responses. We observed a statistically significant reduction in CTCs counts in the clinical responders. We performed long-term follow up with serial CTC collection and enumeration in one patient observing variations in counts correlating with treatment response. This study demonstrates the consistency of the NanoVelcro Chip assay over time for CTC enumeration and also shows that continuous monitoring of CTC numbers can be employed to follow responses to different treatments and monitor disease progression.