CLDN3 and neoplasm: Importantly, the intratumoral injection of cytotoxic Clostridium perfringens enterotoxin (CPE) that interacts with claudin-3 and claudin-4 in subcutaneous serous EC xenografts led to tumor disappearance and extended survival of animals [65], indicating that targeting claudin-3 and claudin-4 by CPE or other targeted treatment may efficiently suppress the progression of EC.