title: Correlation between Cancer Stem Cells and Circulating Tumor Cells and Their Value.
abstract: BACKGROUND
  The scientific community has proven the value of circulating tumor cells (CTCs) as a prognostic factor in the development of cancer and progress to metastases [1, 2, 3, 4]. Simultaneously, a new type of cancer stem cell-like (CSC-like) cells has also been established as a progenitor of metastases and relapses in cancer patients [5, 6]. The present research attempts to support the hypothesis that CTCs have all the cellular hallmarks of CSC-like cells which play a crucial role in cancer spreading.
  
  
  METHODS
  TWO METHODS HAVE BEEN CHOSEN: a cellular-based and a molecular-based method. The first method is based on the fact that CSCs form microspheres in culture. In the second method, microspheres develop in the presence of specific markers that define the CSC phenotype [6].
  
  
  RESULTS
  In cellular-based assays, it has been shown that microspheres form in semi-suspension in a culture flask. In the second panel of the test, Nanog was chosen as a marker and the tested sample was positive when grown under specific conditions.
  
  
  CONCLUSIONS
  Our analysis has demonstrated that in this particular case, CSCs-like cells are included in the vast majority of CTCs.
authors.affiliation: Research Genetic Cancer Center (R.G.C.C. Ltd.), Filotas, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Toloudi
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Apostolou
authors.forename: Marina
authors.initials: M
authors.lastname: Chatziioannou
authors.forename: Ioannis
authors.initials: I
authors.lastname: Papasotiriou