tokens: The aim of this study was 1 ) to explore alterations in the TP53 gene with respect to resistance to a regular dose epirubicin regimen ( 90 mg / m2 body surface every 3 week ) in patient with primary , locally advanced , breast cancer ; 2 ) To explore defects in potential mechanisms activating p53 in response to DNA damage in breast cancer as a cause of drug resistance in wild - type tumors .