PIK3CA and neoplasm: In this case, a missense mutation within exon 7 in PIK3CA gene p.C420R could be found, which led to the change from T to C at base 1258, thereby inducing an alteration from cysteine to arginine at amino acid 420, while this contributes to the sustained PI3K/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway activation, thus promoting tumor development (7).