PIK3CA and breast cancer: Moreover, despite the apparent lack of HR deficiency (as defined by [26, 27]) in older TNBC patients (including LAR subtype cases), these still resembled basal-like breast cancer more than, e.g., ER-positive luminal B disease with respect to genome-wide copy number alterations (Additional file 3), albeit with an increase of amplification drivers and PIK3CA mutations as previously noted [19].