PIK3CD and cancer: Currently mTOR inhibitor rapalogs (such as temsirolimus and everolimus) and PI3K inhibitors (Copanlisib, a pan-class I PI3K inhibitor and Idelalisib, a PI3Kδ Inhibitor) are the only commercially available anti-cancer drugs targeting PI3K/mTOR pathway, validating PI3K and mTOR as crucial therapeutic targets in cancer [41–43].