MIB1 and neoplasm: Instead, significant positive associations were seen with markers of aggressive tumor phenotype such as basal-like markers including cytokeratin (CK) 5/6 and EGFR (p<0.0001), and the proliferation marker MIB1 (p<0.002), mutated p53 and BRCA1 (p<0.0001), and HER2 (kappa: p=0.004).