CLDN5 and head and neck cancer: For example, CLDN3 and CLDN4 are upregulated in ovarian, endometrial, and pancreatic cancers (where they may confer growth and survival advantages), whereas CLDN5 and CLDN7 are commonly downregulated in lungs, colon, and head/neck cancers (consistent with their role in maintaining a less invasive epithelial state).