Chadwick Boseman's death is bringing attention to colon cancer among young people.

The “Black Panther” star died at 43 years old after a four-year battle with the illness. His diagnosis is part of an alarming trend.

“There is definitely an increase in younger patients with colon cancer, and by that we generally mean patients under age 40,” says oncologist Dr. Howard Hochster.

Hochster is part of the Rutgers Cancer Institute of New Jersey and has specialized in treating colon cancer for more than 20 years. He says that symptoms in young patients can be overlooked.

“Many doctors think patients are too young to get colon cancer if they’re in their 30s. And unfortunately, I’ve seen quite a few who are diagnosed late because their doctor didn’t believe them,” he says.

A study put out earlier this year by the American Cancer Society found that cases of colorectal cancer in people under the age of 50 is rising by more than 2% a year, even as the rate is declining in people over the age of 65. The study could not conclude why this is the case.

Boseman was diagnosed with colon cancer four years ago, according to a family spokesperson. He completed some of his most famous films, including Marvel’s “Black Panther,” while undergoing treatment, including surgery and chemotherapy.