ERBB2 and cancer: Luminal B (HER2+) PR+ cancers were significantly more likely to be early-stage(stage I) than luminal B (HER2+) PR– cancers (32.0% vs. 15.6%, respectively;P=0.001), but there was no significant difference in stage between the luminalB (HER2–) PR+ and luminal B (HER2–) PR– subtypes.