“Isolation of rare circulating tumour cells in cancer patients by microchip technology” Nagrath et al. Nature 2007 Peter Bojo

Big Picture Potential uses of CTCs –Choice of therapy –Monitoring of therapy –Explaining the biology of metastasis Microchip is one of many CTC technologies –Immunomagnetic beads –Total RNA qPCR

Microchip Design Blood pumped through forest of posts ~80,000 posts on a ~10cmX10cm chip EpCAM antibodies on posts Testing with cancer cell spiked solutions determines: –Flow rate ~1mL/hr –High capture efficiency even for low EpCAM expression levels ~60% –Identical capture efficiency for whole blood and lysed blood

Microchip Workflow 1. Take whole blood sample, flow through optimized chip 2. Stain with DAPI, cytokeratin, and CD45 antibodies. 47% purity 3.Analyze CTC sensitivity, viability, and predictive ability

Cancer Patient CTC Experiment NSCLC, prostate, pancreatic, breast, and colon cancer samples. Metastatic and non-metastatic prostate cancer samples. Isolated between 5 and 1300 CTCs per patient in 115/116 cases. 0 CTCs in healthy samples High sensitivity

Predictive Ability for Cancer Treatment

Conclusions Microchip is a competitive CTC enrichment technology Uses unprocessed blood High purity of isolated cells: 47% High sensitivity: 99% Capture efficiency: ~60% High cell viability:98% Further Study warranted for: –CTC count and tumor size correlation –Comparable numbers of CTCs in localized and metastatic cancers