title: CD44 as a molecular marker to screen cancer stem cells in hypopharyngeal cancer.
abstract: CONCLUSIONS
  The CD44(+) cells have a stronger proliferative capacity and higher tumorigenic potential than the CD44(-) cells, which suggests that the cancer stem cells of hypopharyngeal cancer may exist in the CD44(+) tumor cell population. Therefore, we propose that CD44 is an important biological marker to screen cancer stem cells of hypopharyngeal cancer.
  
  
  OBJECTIVE
  To study the significance of CD44 as a molecular marker for screening cancer stem cells in hypopharyngeal cancer.
  
  
  METHODS
  The CD44 expression levels in the hypopharyngeal cancer cell line FaDu were analyzed using flow cytometry. To investigate the biological significance of the CD44(+) population, we sorted the CD44(+) and CD44(-) cell populations by using magnetic-associated cell sorting (MACS) technology. After the separation, the purity of the CD44(+) cells was determined using flow cytometry. The MTT method was used to detect the different proliferation capabilities of the CD44(+) and CD44(-) cells in vitro. The tumorigenicity of the CD44(+) and CD44(-) cells was determined by injecting CD44(+) or CD44(-) cells (1 × 10(6) and 1 × 10(5)) into the body of NOD/SCID mice.
  
  
  RESULTS
  Some (21.1 ± 1.56)% of the hypopharyngeal cancer cell line FaDu cells expressed CD44. The CD44(+) population was efficiently sorted by MACS, and after separation, the purity of the CD44(+) cells was (99.4 ± 0.29)%. The MTT assay indicated that the sorted CD44(+) cells had a stronger proliferative capacity than the CD44(-) cells. The tumorigenicity study showed that all the mice injected with 1 × 10(6) CD44(+) cells developed tumors (8/8), half the mice injected with 1 × 10(6) CD44(-) cells developed tumors (4/8), 1 of the 8 mice injected with 1 × 10(5) CD44(+) cells developed tumors (12.5%), but none of the mice injected with 1 × 10(5) CD44(-) cells developed any tumors (0/8). At the same concentration, the difference in tumorigenic rates between the CD44(+) and CD44(-) groups was statistically significant (Fisher's exact test, p < 0.05). Furthermore, the CD44(+) group had a shorter incubation period than the CD44(-) group. In addition, the average tumor volume of the CD44(+) group was (2017.81 ± 538.50) mm(3); however, the average tumor volume of the CD44(-) group was (1153.25 ± 503.18) mm(3). The difference was statistically significant (t = 2.67, p < 0.05).
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, The Ear Institute, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.
authors.forename: Chenling
authors.initials: C
authors.lastname: Shen
authors.forename: Mingliang
authors.initials: M
authors.lastname: Xiang
authors.forename: Chen
authors.initials: C
authors.lastname: Nie
authors.forename: Haixia
authors.initials: H
authors.lastname: Hu
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Hao
authors.initials: H
authors.lastname: Wu
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D007012:Hypopharyngeal Neoplasms / Q000378:metabolism*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C497483:CD44 protein, human; D018960:Hyaluronan Receptors