Recent studies suggested that the prostate cancer may arise from prostate cancer stem cells that share some same characteristics with normal stem cells.The purpose of this study was to detect the differences of Nanog expression between PC3 prostate cancer cell line and its tumor stem cells,and fhe relationship was preliminarily examined between Nanog and prostate cancer and its tumor stem cells.By using magnetic active cell sorting (MACS),we isolated a population of CD44+/CD133+ prostate cancer cells that display stem cell characteristics from PC3 cell line.lmmunohistochemistry revealed positive expressions of CD44,C D 133 and α2β1-integin in the isolated cells.CCK-8 analysis showed that isolated cells had a strong proliferafive ability.The formation of the cell spheres in serum-free medium and holoclones in serum-supplied medium showed that the cells were capable of self-renewing,indicating that the isolated cells were a population of cancer stem-like cells derived from PC3 cell line.West blotting exhibited that the isolated cells had higher experession of Nanog,an embryonic stem marker,as compared with PC3 cells.Our study showed that Nanog might be helpful in sustaining the self-renewal and fhe undifferentiation of prostate cancer stem cells,and may serve as a marker for prostate cancer stem cells for isolation and identification.