Cells and a stiff material called the matrix can squeeze blood vessels in tumors and thus block delivery of cancer-fighting drugs to malignant cells. Now researchers may have a way to reopen vessels and restore the drugs' power
For nearly 40 years, I have been working on fighting cancer from an unusual angle. Trained initially as an engineer, I see tumors in part as a physics challenge and ask: How do their structural features promote their growth and keep cancer-fighting drugs from working effectively?
More than two decades ago, for instance, my co-workers and I, then at Carnegie Mellon University, revealed that structural abnormalities in tumor blood vessels interfere with drug delivery to malignant cells in a mass. These vessels tend to be overly twisty and porous, and the porosity leads fluid and drugs in the blood to leak out as blood enters a mass. The fluid then exerts an outward pressure that causes it and the drug molecules to ooze out of the tumor into the surrounding tissue. We later showed that reducing the leakiness could also lower this so-called interstitial fluid pressure and improve drug distribution in the tumor, thereby enhancing responses to various treatments meant to attack cancer cells.