PIK3CD and neuroblastoma: Another pan-PI3K inhibitor, pictilisib, was also cytotoxic to these neuroblastoma cell lines but less effective than copanlisib, as revealed by the inhibitory curve (Fig. 2c), despite that pictilisib treated NBL-S, IMR-32, and LA1-5s failed to reach 50% of inhibition due to its poor solubility (data not shown).