PIK3CA and breast cancer: Yates et al. [24] applied multi-region sequencing to 303 breast cancer samples and no strict temporal order was perceived in subclonal diversification across breast cancer subtypes, suggesting commonly seen point mutations (clonal mutations) such as PIK3CA, TP53, PTEN, BRCA2 (somatic) and MYC may take place any time in tumor initiation and progression.