RESUMO
BACKGROUND: The dissemination of circulating tumor cells (CTCs) that cause metastases in distant organs accounts for the majority of cancer-related deaths. CTCs have been established as a cancer biomarker of known prognostic value. The enrichment of viable CTCs for ex vivo analysis could further improve cancer diagnosis and guide treatment selection. We designed a new flexible micro spring array (FMSA) device for the enrichment of viable CTCs independent of antigen expression. METHODS: Unlike previous microfiltration devices, flexible structures at the micro scale minimize cell damage to preserve viability, while maximizing throughput to allow rapid enrichment directly from whole blood with no need for sample preprocessing. Device performance with respect to capture efficiency, enrichment against leukocytes, viability, and proliferability was characterized. CTCs and CTC microclusters were enriched from clinical samples obtained from breast, lung, and colorectal cancer patients. RESULTS: The FMSA device enriched tumor cells with 90% capture efficiency, higher than 10(4) enrichment, and better than 80% viability from 7.5-mL whole blood samples in <10 min on a 0.5-cm(2) device. The FMSA detected at least 1 CTC in 16 out of 21 clinical samples (approximately 76%) compared to 4 out of 18 (approximately 22%) detected with the commercial CellSearch® system. There was no incidence of clogging in over 100 tested fresh whole blood samples. CONCLUSIONS: The FMSA device provides a versatile platform capable of viable enrichment and analysis of CTCs from clinically relevant volumes of whole blood.
