PIK3CA and neoplasm: Studies have shown that Vorinostat not only activates p21 expression to induce cell cycle arrest and apoptosis [43], but also interferes with tumour cell proliferation, metabolism, and survival by regulating multiple signalling pathways such as NF‐κB, JAK/STAT, PI3K‐AKT and mTOR [44, 45, 46, 47].