title: CD24 is a new oncogene, early at the multistep process of colorectal cancer carcinogenesis.
abstract: OBJECTIVE
  The aim of this study was to identify genes that play a role in colorectal cancer (CRC) carcinogenesis by analysis of differential gene expression of normal and transformed CRC cell lines.
  
  
  METHODS
  Gene expression array analysis ([RG-U34] GeneChip) was performed in normal and transformed rat intestinal epithelial cells before and after exposures to celecoxib. In particular, we were looking for (1) altered gene expression in the transformed cells that reverts to normal following exposure to a selective cyclooxygenase-2 inhibitor, (2) novel genes, and (3) genes encoding membrane receptors or ligands. As a validation of the results and for human patients, immunohistochemistry was performed on 398 biological samples from the gastrointestinal tract (normal, polyps, and adenocarcinomas). Human cancer cell lines were tested for their response to anti-CD24 monoclonal antibodies.
  
  
  RESULTS
  A total of 1081 genes were differently expressed following malignant transformation; 71 genes showed altered expression that reverted to normal following treatment with celecoxib, including the CD24 gene. Immunohistochemistry confirmed that increased expression of CD24 is an early event in CRC carcinogenesis. It was expressed in 90.7% of adenomas and 86.3% of CRCs. Very low expression was seen in normal epithelium (16.6%). Human cancer cell lines showed growth inhibition in response to the antibodies, according to their expression levels of CD24 and in dose- and time-dependent manners. These results were repetitive for 3 different antibodies.
  
  
  CONCLUSIONS
  CD24 is overexpressed in the colonic mucosa, already at an early stage of carcinogenesis. It may be a useful target for early detection and in CRC therapy.
authors.affiliation: Department of Cancer Prevention, Tel Aviv Medical Center, Tel Aviv, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Sagiv
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Memeo
authors.forename: Adi
authors.initials: A
authors.lastname: Karin
authors.forename: Diana
authors.initials: D
authors.lastname: Kazanov
authors.forename: Jasmin
authors.initials: J
authors.lastname: Jacob-Hirsch
authors.forename: Mahesh
authors.initials: M
authors.lastname: Mansukhani
authors.forename: Gidi
authors.initials: G
authors.lastname: Rechavi
authors.forename: Hanina
authors.initials: H
authors.lastname: Hibshoosh
authors.forename: Nadir
authors.initials: N
authors.lastname: Arber
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D051927:CD24 Antigen / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D012334:RNA, Neoplasm / Q000235:genetics* / Q000378:metabolism; D051381:Rats
chemical_list: D014408:Biomarkers, Tumor; D051927:CD24 Antigen; C497889:CD24 protein, human; D012334:RNA, Neoplasm