As overexpression of claudins serves as a marker for malignant progression in some tumors,55 most notably breast cancer,56 and given the multiple links between the subcellular localization of claudins, IQGAP1, TJs, and EGFR signaling, additional studies on claudin localization in the context of claudin-overexpressing EGFR-dependent tumors is warranted. This evidence concerns the gene EGFR and breast cancer.