Non-Oncology Applications: 9 of 14

Digestive Disease

This category covers non-cancer diseases of the digestive system and the organs connected to it. A major part of the research involves inflammatory bowel disease, the umbrella term for Crohn's disease and ulcerative colitis. It also includes liver disease, celiac disease, and pancreatitis.

For inflammatory bowel disease, the reference procedure is endoscopy. A camera on a flexible tube is passed into the bowel so doctors can see the lining and take small tissue samples. It gives useful information, but patients have good reasons to dislike it: the bowel has to be emptied beforehand, sedation is common, and the whole process can take up much of a day. Liver disease has its own invasive reference test, a needle biopsy through the abdominal wall, which carries a risk of bleeding.

These are often lifelong diseases, so testing is repeated over many years. The burden adds up.

There is already a useful non-blood alternative for bowel inflammation. A stool test can measure a protein released by inflammatory cells and does a good job of showing how inflamed the bowel is. That means a blood test has to improve on something that already works or answer a different question.

Researchers are interested in telling Crohn's disease from ulcerative colitis when the diagnosis is unclear, predicting who is likely to have a more aggressive course, spotting a flare before symptoms return, and checking whether the bowel lining has truly healed. That last question still often requires a camera. In liver disease, one of the main goals is estimating how much scarring is present, since the amount of scarring affects the risk of serious complications and is otherwise measured with biopsy or specialized imaging.

Broad blood tests for inflammation are not specific enough for many of these jobs. They can rise because of inflammation almost anywhere in the body, from a chest infection to an injured joint. Newer markers try to point more specifically to the gut or liver. Proving that they really do come from the tissue of interest, rather than simply marking that someone is unwell, is the difficult part.