Fig. 5

Two-photon laser-scanning microscopy (2P-LSM) reveals cellular responses of microglia to tumor injections in vivo in TgH(CX3CR1-EGFP) mice. a–c Microgliosis around the tumor injection site (circle), 30 min after implantation. White triangles point to mCherry-GL261 cells infiltrating the brain cortex. d–f At 36 h, microglial cells presented either a typical amoeboid shape (orange squares, d) or a ramified morphology, with a small cell body and long processes (white squares, d). mCherry-GL261 cells were present in capillary borders, suggesting a route for cancer cell spreading (white arrows, e and f). g–i Microglia remained infiltrated and in close contact with tumor cells, suggesting a cell-cell communication during tumor growth. Scale bars: (a–f), 50 μm; (g–i), 20 μm