ERBB2 and breast cancer: The correlation between these mutations and breast cancer prognosis is less clear, with several studies reporting associations between PIK3CA mutations and lymph node metastasis and worse overall and breast cancer-specific survival (Saal et al, 2005; Li et al, 2006; Lai et al, 2008; Aleskandarany et al, 2010), whereas other studies have reported associations with longer survival particularly among patients with ER-positive, HER2-negative tumours (Perez-Tenorio et al, 2007; Kalinsky et al, 2009; Loi et al, 2010).