PIK3CD and cancer: Targeted therapies for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), ROS1 and BRAF have resulted in marked improvements in survival, particularly for patients with advanced disease.2 Increased activation of the phosphatidylinositol 3‐kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway leads to numerous hallmarks of cancer, including acquired growth signal autonomy, inhibition of apoptosis, sustained angiogenesis, increased tissue invasion and metastasis and insensitivity to antigrowth signals.