Demonstration of selective tissue microdissection of a relatively pure population of tumor cells. Left, a hypercellular focus of GBM cells, abutting the acellular space to the left of the slide, surrounded on the right by white matter (brain) infiltrated by tumor cells, but at a substantially lower cellular density; middle, the tumor cells selectively removed by LCM; and, right, the tumor cells isolated on the LCM cap.