PTEN and cancer: We have reported that many cancers exhibit a dysregulated nuclear factor-kappaB (NF-κB)/Snail/Yin Yang 1 (YY1)/RKIP/PTEN loop that primarily is responsible for the phenotypic properties of cancer cells, namely, cell proliferation and viability, migration and metastasis, and resistance to both cytotoxic drugs and to cytotoxic T and natural killer (NK) cells [7, 8].