CYP19A1 and metastatic neoplasm: Although the current study was conducted in a patient population distinct from that of the PALOMA-2 trial (i.e., patients in the current study were older, and more patients had only 1 metastatic site, bone-only disease, and de novo metastatic disease), the median rwPFS with first-line palbociclib plus an aromatase inhibitor observed herein (31.7 months) was complementary to the median PFS reported in PALOMA-2 (24.8 months) [9,11].