TP53 and breast neoplasm: However, as compared with HR-negative breast tumors, those with HR-positive status had significantly fewer TP53 mutations among HER2-zero (33.3% [20/60] vs. 86.7% [26/30], p < 0.001) and HER2-low (26.2% [53/202] vs. 72.4% [21/29], p < 0.001), but not among HER2-positive breast tumors (79.7% [94/118] vs. 85.7% [72/84], p = 0.351) (Additional file 1: Fig. S6A).