8Parkin D M.Global cancer statistics in the year 2000[J].Lancet Oncol,2001,58(2):533-543.
9Li D W,Tang H M,Fan J W,et al.Expression level of Bmi-1oncoprotein is associated with progression and prognosis in colon cancer[J].J Cancer Res Clin Oncol,2010,136(7):997-1006.
10Reya T,Morrison S J,Clarke M F.Stem cells,cancer and cancer stem cells[J].Nature,2001,414(6859):105-111.