ERBB2 and breast cancer: As both MCF-7 and ZR-75-1 cells belong to ER-positive subtype of breast cancer, in order to assess other subtypes of mammary carcinomas, we have carried out PRDX1 knockdown in five additional cell lines: non-malignant MCF-10A,30 T47D (ER-positive cancer), MDA-MB-231 (triple-negative cancer), HCC 1806 (triple-negative cancer), and SK-BR-3 (HER2-positive, ER-negative cancer).