Thus, CTBE cells showed both p63 and CK5 over-expression together with a significant loss of BRCA1 expression and ER negativity, all consistent basal breast cancer phenotype (Liu et al. 2008; Ribeiro-Silva et al. 2005), which may indicate a loss of differentiation capacity during the acquisition of basal malignant phenotype. The gene discussed is KRT5; the disease is breast carcinoma.