Claudin 1, 3, 4, and 7 expression in triple-negative breast cancer.

1070 Background: Triple negative breast cancer (TNBC) often grows rapidly and has poor prognosis, with a high recurrence rate. Because conventional endocrine treatment and HER2 targeted therapy for TNBC is invalid, chemotherapy is the only systemic treatment for TNBC. It is known that several subtypes within the TNBC show different responses to chemotherapy, depending on the subtypes. Recently, a claudin (CLDN) low breast cancer has been identified, exhibiting low expressions of CLDNs 1, 3, 4 and 7. CLDNs are transmembrane proteins that seal tight junctions and are critical for maintaining cell-to-cell adhesion in epithelial cell sheets. However, their role in cancer progression remains largely unexplored. Methods: Surgically removed, formalin-fixed, paraffin-embedded breast cancers from 341 TNBC patients were analyzed to identify CLDN expression.They underwent wide local excision or mastectomy between March, 2004 and December, 2007 at the breast surgery unit of Asan Medical Central Hospital. Results: In ...