Tumors Make Their Own Blood Vessels

We believe one of the ways cancerous tumors grow is by inducing cells that form blood vessels to grow new ones to feed it; a process called angiogenesis. But about twenty years ago, scientists hypothesized that tumor cells themselves can form blood vessels, a process called vasculogenic mimicry or VM. That started a fierce debate about how tumors acquire their blood supply.

Today, a new drug that targets VM has gone into clinical trials and if successful would bolster the VM idea. This shift in focus is partly because drugs that try to block angiogenesis merely slow tumor growth temporarily. Accumulating evidence now suggests VM is the reason.

In one experiment scientists grew rapid growing melanoma cancer cells in a gel that mimics the matrix they'd naturally be growing in, inside the body. The cells migrated through the matrices and 'scrunched it up' forming a network of channels that looked like chicken wire. These channels contained red blood cells just like the ones you'd find inside a normal blood vessel, showing tumor cells may indeed have the capability of creating their own blood vessels.

We could see this at work inside the body of a cancer patient in a later study. When researchers injected a fluorescent dye into the arms of eye melanoma patients, remarkably, the dye made it from the arm, into the eye, and the tumor channels in thirty seconds. These channels feed tumors with nutrients and oxygen and possibly help them spread to other parts of the body.

A drug company in Taiwan gave these researchers a drug called CVM-1118 which was able to block VM by interfering with a gene that drives this process. So, the drug is being tested with the hope it will become a new cancer fighting tool.