The imaging probes in this study were chosen to highlight three main compartments in the tumor (figure 1B): cancer cells via an epithelial antigen (CD326, EpCAM commonly used to detect circulating cancer cells and overexpressed on a wide variety of epithelial cancers[17]), functional supporting microvasculature (a probe with prolonged distribution in the plasma volume), and stromal tissue (easily targeted innate immune cells, such as the CD11b pool). Here, EPCAM is linked to neoplasm.