In a series of studies, the group of Kikuchi et al. demonstrated activation of the intrinsic apoptosis pathway, G1 phase arrest, and expression of PTEN, a significant negative regulator of the PI3K/Akt, and naringin, a polyphenolic flavonoid derived from grapefruit and other citrus fruits that has been proven to possess a chemo-sensitizing effect, synergistically strengthening the anticancer potential of paclitaxel in human prostate cancer cells, regardless of androgen dependence [115]. This evidence concerns the gene AKT1 and prostate cancer.