NR4A1 and neoplasm: While statistically significant differences between HER2-low and HER2-zero tumours were detected for several of the variables, the more prominent differences included the higher percentage of HER2-low tumours in the hormone receptor-positive subgroup than the hormone receptor-negative subgroup (45.9% vs 29.4%, P < 0.001) and among the hormone receptor-positive BCs tumours diagnosed more recently during 2011–2015 (62.9% vs 46.8%).