PIK3CA and neoplasm: In our study cohort, most of mutated genes in either tumor DNA or ctDNA, including TP53 and PIK3CA, both of which play important roles in tumorigenesis and progression (Muller and Vousden, 2013; Oren and Rotter, 2010; Silwal‐Pandit et al., 2014; Zardavas et al., 2014), presented higher mutation frequencies than those reported in TCGA.