I don't know about main suspect, but autoimmune disease has been known for a long time to increase your risk of cancer. I have Celiac disease, so an increased risk of stomache, intestinal and bowel cancer.

Honestly, this article is kind of worrying for me, personally. I have many symptoms after two years of treatment with diet alone. Further evidence may eventually show treatment with antibiotics or steroids for people like me may lower more risks then it raises.

Cancer has many different, simultaneous causes. That's why when people say "x causes cancer" what they mean is x (whatever it is) raises your odds of getting cancer by a measurable degree.

As someone with both that sucks