MKI67 and metastatic neoplasm: Although the sample sizes of the 2 studies were different (42 in J-Ph2 vs 444 in PALOMA-2) and precise comparison is challenging, similar baseline patient demographics and disease characteristics were observed for patient median age (62.5 vs 62 years), percentage of patients with visceral disease (47.6% vs 48.2%), endocrine-resistant disease (TFI ≤ 12 months; 19.0% vs 22.3%), de novo metastatic disease (33.3% vs 37.6%), ≤ 20% Ki67-positive expression (45.2% vs 58%) and patients with previous (neo)adjuvant ET (64.3% vs 56.1%) [8, 10, 17].