PIK3CA and cancer: Among the 10 top up‐regulated and down‐regulated genes, PITX2, SNCA, and EPHA7 (up), as well as TMEM98 (down) are indirect upstream regulators of PI3K/AKT signaling pathway, contributing greatly to the development of chemo‐resistance in cancer via promoting cell proliferation, survival, and cell cycle progression as well as inhibiting apoptosis.