EI24 and neoplasm: EI24 is a tumor suppressor protein26,29 and is often mutated in cancer cells.24–27 Loss of EI24 leads to resistance to DNA damage-induced cell death29 and dysfunction in DNA damage-induced apoptosis results in tumorigenesis and drug resistance in cancer cells.63 Combined with the observation that reduced Ca2+ transfer from the ER to mitochondria in cancer cells accelerates tumor growth,64 our findings may explain why EI24 is frequently lost or mutated in cancers.