TP53 and cancer: Importantly, revealed by intravital fluorescent microscopy, this critical crosstalk between the SERCA pump and p53 in generating apoptotic signals is also substantiated in vivo in cancer photodynamic therapy using light-activated photosensitizer phthalocyanine, linking p53 sensitization of cellular apoptosis to ER Ca2+-overload and increased mitochondrial Ca2+ uptake [178].