Researchers Solve 15-Year Mystery Behind Cancer-Causing Gut Toxin

A Johns Hopkins-led team identified claudin-4 as the receptor Bacteroides fragilis toxin uses to attack colon cells.

Using CRISPR screening and structural studies, the researchers showed BFT must bind claudin-4 before it can cause damage.

They also built a decoy receptor that reduced toxin injury in animal tests, suggesting a possible prevention strategy.

The finding clarifies a long-standing mechanism for a gut toxin linked to colorectal cancer risk.