PIK3CA and cancer: In order to further study the potential significance of these high frequency neoantigens, we focused our attention on the mutation R175H (TP53), H1047R (PIK3CA), and G12D (KRAS) because these sites can not only produce recurrent neoantigens (frequency of more than 4 occurrences in 482 samples) but also have high mutation frequencies in the TCGA pan-cancer cohort.