MKI67 and breast cancer: Figure 3 shows that BC presenting a low amplification rate (4.0–5.9 HER2 s/n, CEP17 = 2.0) have a significantly higher percentage of ER (p = 0.016) and/or PgR positivity (p = 0.001) and a lower percentage of Ki67 proliferation index (p = 0.027) than highly amplified tumors (>6.0 HER2 s/n).