PIK3CD and malignant endocrine neoplasm: Given the fact that PI3Kδ and PI3Kδ-S exhibit differential oncogenic activities, our data suggested that a potential of utilizing the PIK3CD-S/PIK3CD-L (or PI3Kδ-S/PI3Kδ-L) expression profile as an index to evaluate the tumor aggressiveness in endocrine cancers.