Figure 3.

Glioma cells invade the adjacent host tissue by perivascular migration along host and tumor blood vessels. (a and b) Epifluorescence intravital video microscopy of C6 glioma periphery on day 14. Same region of interest as assessed by using the filter systems to detect FITC-Dextran–labeled blood vessels (a) and DiI-labeled tumor cells (b). Individual tumor cells (arrows) localize to the vicinity of tumor blood vessels. (c–e) Three-dimensional reconstruction of multiphoton laser scanning microscopy confirms colocalization of infiltrative tumor cells (blue) and tumor blood vessels (green). The multidirectional view of 3-D imaging can separate truly perivascular (arrowheads) from only seemingly perivascular (arrows) cells. Bars represent 50 μm (b and e).