To verify the functional effects of PIK3CD-L and PIK3CD-S in endocrine and solid tumors expressing PIK3CD-L and PIK3CD-S splice variant, the cancer cell lines were transfected with nonsense siRNA (NS), siPIK3CD, siPIK3CD-L (siRNA targeting exon 20 of PIK3CD), or siPIK3CD-S (siRNA targeting junction of exon 19 and 21) for 48 h then the transfected cells were harvested and subjected to western blot analysis for examining the protein levels of the AKT/mTOR signaling components. The gene discussed is PIK3CD; the disease is cancer.