PIK3CA and thymoma: In addition, gene expression analysis reveals over-expression of PIK3CA (aka PI3K p110), the canonical activator of AKT.To confirm, we performed a quantitative ELISA on a validation set of 35 thymomas for phospho-AKT (Ser 473), and demonstrate that C19MC positive thymomas have significantly higher levels of phospho-AKT compared to C19MC negative thymomas which in-turn has higher levels than adjacent normal tissue.