PIK3CA and cancer: In the TP53 wild-type samples (n = 28), the PI3K pathway appeared to be a predominant driver with 19 samples (68%) containing a mutation in either the PIK3CA gene or PI3K pathway members, including PIK3C2B, PIK3CG and PTEN. In the TP53 mutant group, 67 samples (76%) had one or more mutations in genes encoding chromatin remodeling proteins, including ATRX, DNMT3A and KMT2C, which have been reported to be involved in cancer.