PTEN and neoplasm: When we combined tumours with a PIK3CA/ERBB family mutation and/or PTEN loss (i.e., PI3K pathway activated), we found no difference in pCR rates between 25 patients with PI3K activated tumours and 20 patients with tumours without an activated PI3K pathway (44% vs. 50%; p = 0.769) (Fig. 3).