PPIF and cancer: Many cancer models inhibit cell death in response to fluctuations of the PTP effectors, such as Ca2+or Mg2+, reactive oxygen species (ROS), and matrix pH [29], or controlling the PTP association with its physiological inducer, the cyclophilin D (CyPD) [30–32], which modulates ATP synthase activity [33], binding its OSCP subunit [30].