用一种特别的激光扫描方法，科学家们观察到了大脑中癌细胞转移建立的过程，新成果发表在12月在线出版的《自然—医学》期刊上。

脑癌患者通常会发生致命性的癌细胞转移。用一种名为多光子激光扫描显微镜的技术，Frank Winkler和同事实时观察到了转移过程形成的每个步骤。他们还能在几分钟到几个月的时间里，跟踪小鼠大脑深处血管中单个转移癌细胞的命运。

科学家们已经确立出一整套的关键性步骤：在血管分枝处捕捉癌细胞、退出血管、持续联结细胞和毛细胞，最后，在血管周围转移癌细胞。在活体中观察到大脑癌细胞转移形成的过程，将有助于科学家们深入了解癌细胞的发展过程，并确立出相应的治疗方法。

原始出处：

Nature Medicine 20 December 2009 | doi:10.1038/nm.2072

Real-time imaging reveals the single steps of brain metastasis formation

Yvonne Kienast1,2, Louisa von Baumgarten1, Martin Fuhrmann2, Wolfgang E F Klinkert4, Roland Goldbrunner3, Jochen Herms2,5 & Frank Winkler1,5

Brain metastasis frequently occurs in individuals with cancer and is often fatal. We used multiphoton laser scanning microscopy to image the single steps of metastasis formation in real time. Thus, it was possible to track the fate of individual metastasizing cancer cells in vivo in relation to blood vessels deep in the mouse brain over minutes to months. The essential steps in this model were arrest at vascular branch points, early extravasation, persistent close contacts to microvessels and perivascular growth by vessel cooption (melanoma) or early angiogenesis (lung cancer). Inefficient steps differed between the tumor types. Long-term dormancy was only observed for single perivascular cancer cells, some of which moved continuously. Vascular endothelial growth factor-A (VEGF-A) inhibition induced long-term dormancy of lung cancer micrometastases by preventing angiogenic growth to macrometastases. The ability to image the establishment of brain metastases in vivo provides new insights into their evolution and response to therapies.

1 Department of Neurology, Ludwig-Maximilians University, Munich, Germany.
2 Department of Neuropathology, Ludwig-Maximilians University, Munich, Germany.
3 Department of Neurosurgery, Ludwig-Maximilians University, Munich, Germany.
4 Max Planck Institute of Neurobiology, Martinsried, Germany.
5 These authors contributed equally to this work.