ANPEP and cancer: In addition, inhibition of the UCK2 enzyme activity by FKB and APN exhibited a strong correlation to the MDM2-p52 signalling pathway, in which current investigations have demonstrated the ability of FKB and APN in the destruction of the MDM2-p53 complex, in turn, being the cause of the activation of p53, which is essential in triggering cell cycle arrest and apoptosis induction in the cancer cells.