PIK3CA and breast cancer: DNA analysis from the phase III APHINITY trial, randomizing patients with HER2+ early BC to receive adjuvant chemotherapy plus Trastuzumab and Pertuzumab versus chemotherapy plus Trastuzumab and placebo, revealed that PI3K/Akt/PTEN alterations (comprising PTEN homozygous deletion or any PTEN alteration) predicted worse outcome in terms of invasive DFS in a pooled analysis of both treatment arms [34].