Detection and Enumeration of Circulating Tumor Cells with Invasive Phenotype

Circulating tumor cells (CTCs) disseminate from solid primary cancers into the peripheral blood and lymphatic vessels and can lead to metastatic tumor development; thus, CTC assays are an important clinical tool for monitoring progression and evaluating prognosis in cancer. However, CTCs are limited in number and heterogeneous in their biological and physical properties, making their detection, isolation, and enumeration a major challenge. To overcome these difficulties, novel techniques have been developed to detect and enumerate CTCs with an invasive phenotype. In this chapter, we will summarize these recently developed methods and detail two novel methods for capturing and enriching CTCs on the basis of their viability and their invasive properties.