CDKN1B and Familial prostate cancer: Thus, they concluded that via the MT1/PKA(Gαs)/PKC(Gαq) signaling pathway, melatonin directly inhibited the constitutively active NFκB in prostate cancer cells, resulting in diminished repression of the p27kip1 promoter, thereby upregulating transcription of p27Kip1 [59].