(NBC News) – Some researchers suspect the trend has to do with obesity and diet. Others point to changes in the gut microbiome.

Gastrointestinal cancers, which include colorectal, stomach and pancreatic cancer, are rising dramatically in younger adults, though doctors aren’t fully sure why. Even some of the possible causes require more research, they say.

According to a review published Thursday in JAMA, gastrointestinal cancers have become the fastest-growing type of cancers diagnosed in adults younger than 50 in the U.S. (Read More)