ERBB2 and breast cancer: Our low‐risk TC‐Gx, based on the weighted sum of 37 expression values of genes strongly correlated with TC, was associated with basal‐like (P < 5 × 10−13), HER2‐enriched subtype (P < 5 × 10−07) and worse 10‐year breast cancer‐specific survival (log‐rank P < 5 × 10−04).