PIK3CA and cancer: However, it was not consistent with the fundamental sequencing work of TNBC by Shah et al. [22], in which clonality analysis demonstrated that known driver mutations such as TP53, PIK3CA and PTEN possessed the highest clonal frequencies (suggesting that they were early events in tumorigenesis), whereas mutations involved in cell shape/motility and extracellular matrix-signaling pathways occur at lower clonal frequencies and later on the cancer evolution time scale.