PIK3CD and breast carcinoma: Indeed, PI3K subunits play a key role in oncogenesis: somatic mutations in p110δ (causative for APDS1) have been found in locations analogous to oncogenic variants in p110α and in patients with non-APDS-related DLBCLs; furthermore, tumour-suppressor p85α mutations (causative for APDS2), leading to p110α hyperactivation, have been found in gliomas and colon, endometrial, and breast cancers (14, 29, 30).