An earlier study of 1794 breast cancer patients showed that TP53 mutations were more frequent in PR-negative tumors than those in PR-positive tumors (Olivier et al. 2006) but did not identify HER2 status, remaining unclear whether the TP53 mutation rate is higher in PR-lacking tumors within ER-positive/HER2-negative tumors. This evidence concerns the gene ERBB2 and breast cancer.