Gene Expression Profiling of Circulating Tumor Cells Using the IsoFlux System


  • Gene expression profiling is frequently used in both clinical research and clinical practice to understand tumor subclass, pathway analysis, and other types of clinically-actionable information. 
  • Circulating tumor cells (CTCs) provide a means for analyzing cancer gene expression in a longitudinal manner. The IsoFlux System (Fluxion Biosciences) enables routine CTC collections from a standard blood draw that can then be used for molecular analysis, including gene expression studies.
  • An analytical limit of detection below 5 cells per blood draw was determined by measuring expression of the CTC specific gene KRT19 in spike-in controls. 
  • In a pilot clinical study, a panel of genes associated with risk (KRT19, MAGE-A3, SGCG, TWIST) was compared to enumeration data in breast cancer patients. Of the 6 patient blood samples tested, all were CTC positive as measured by enumeration (CTC count >5 cells) and by KRT19 gene expression.
  • Patients with progressive disease had higher CTC counts and more genes on the panel over-expressed, as compared to patients with stable disease.