Specifically, immunohistochemistry (IHC), immunofluorescence, RT-PCR and western blot assays were performed to examine the expression profiles of PI3Kδ-S/PI3Kδ-L (or PIK3CD-S/PIK3CD-L) in a panel of patient samples and cell lines derived from endocrine/solid tumors, including PCa, breast, pancreatic, colon and lung cancers. Here, PIK3CD is linked to lung cancer.