A recent article about the cell biology of glioblastomas, a very aggressive type of brain tumor, caught my attention (see: Why brain tumors hard to treat). It's a little outside the usual scope of this blog but still fascinating to me. Below is an excerpt from it:
New findings may help explain why glioblastomas, one of the most aggressive forms of brain cancer, are often so difficult to treat -- they can feed themselves, by differentiating into the intricate network of blood vessels that nourish the tumor, according to two [recently published] studies...."The general idea is that the vasculature is created by the normal tissue," said [a] cell biologist ....But these papers show that "the tumor itself is actually making its own blood vessels. It's a very different way to look at them." Glioblastomas are noted for their unusual vasculature, characterized by large, highly proliferating cells and abnormal structures. Until now, however, these vessels were thought to be derived from pre-existing brain capillaries, but no one had ever gone in a taken a close look, said [a] neurosurgeon and neuroscientist ....So she and her colleagues did just that. They looked for mutations known to exist in the tumor cells, including large amplifications and chromosome abnormalities, in the cells of the vasculature to see if they contained a similar genetic signature. Sure enough, a significant proportion of the endothelial cells carried the tumor's mutations, suggesting they originated from the tumor cells....The findings may explain why a common drug used to inhibit angiogenesis in cancer patients may not be very effective....The applications may be more widespread than just glioblastomas.... "All tumors have blood vessels," she said. "I'm hoping that this will invite researchers to look in other cancers to see if other cancers can use this pathway to derive their own blood vessels."
I don't have much to add to this item. Gioblastomas appear to be generating their own blood supply rather than depending on the adjacent normal vessels to provide nutrition. According to two new research studies, the endothelium lining the capillaries intimately associated with the tumor showed some of the same chromosomal abnormalities as the malignant tumor cells themselves. From the perspective of a malignant tumor, this makes perfect sense. Why depend on the adjacent normal tissue for nutrition? The normal cells may have other priorities or may not respond to the tumor cells signaling to increase their vascular supply. It's like people carrying a jerrycan of gasoline in the back of their cars to ensure an adequate supply of fuel.