By screening of 27 colon carcinoma PDX for claudin-3 and/or -4, the clinical relevance of this approach was further supported, as 20 out of 27 PDX models showed both, claudin-3 and claudin-4 expression, whereas 3 revealed the expression of only claudin-3, suggesting, that binding of CPE can occur. Here, CLDN3 is linked to colon carcinoma.