title: Elevated levels and fragmented nature of cellular fibronectin in the plasma of gastrointestinal and head and neck cancer patients.
abstract: BACKGROUND
  Tumor invasion occurs following enzymatic degradation of components of the extracellular matrix. The proteolysis-resistant domains of matrix components are likely to appear in the blood plasma during invasion, and could be used as markers of malignancy. Cellular fibronectin (cFN), a major ECM component, possesses 3 alternately spliced principal protease resistant domains; two of which, extra domain A (EDA) and III connecting segment (IIICS), were selected for this study of the nature of the plasma cFN molecules and its levels in normal subjects (n=51), and patients with gastrointestinal (G-I, n=145) or head and neck (H-N, n=127) cancers.
  
  
  METHODS
  ELISA was used to measure the cFN levels in plasma and Western blotting to analyze its fragmented nature in plasma samples from normal individuals and patients with G-I or H-N cancers.
  
  
  RESULTS
  cFN in blood plasma, as probed by anti-EDA and anti-IIICS antibodies on Western blots, is found to exist entirely in a fragmented form in normal subjects and G-I and H-N cancer patients. The cFN polypeptides in plasma have Mr of 160 and 100. The levels of plasma cFN, determined by ELISA using the 2 antibodies, are found to be increased in G-I and H-N cancers. In a significant number of stomach (43%), gall bladder (35%) and colon (17%) cancer cases an additional anti-EDA-reactive 30 kD peptide is seen in the plasma.
  
  
  CONCLUSIONS
  The mean rise for all sites is statistically significant, and 65% of all patients show cFN levels >80th percentile of normal values. The characterization of the 30 kD peptide showed that it does not contain the IIICS domain and also lacks the central cell- and heparin-binding sites.
authors.affiliation: Biochemistry and Cell Biology, Advanced Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410 208, India. uwarawdekar@actrec.res.in
authors.forename: Ujjwala M
authors.initials: UM
authors.lastname: Warawdekar
authors.forename: Surekha M
authors.initials: SM
authors.lastname: Zingde
authors.forename: K S N
authors.initials: KS
authors.lastname: Iyer
authors.forename: P
authors.initials: P
authors.lastname: Jagannath
authors.forename: Ashok R
authors.initials: AR
authors.lastname: Mehta
authors.forename: Narendra G
authors.initials: NG
authors.lastname: Mehta
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005353:Fibronectins / Q000097:blood* / Q000737:chemistry; D005770:Gastrointestinal Neoplasms / Q000097:blood*; D006258:Head and Neck Neoplasms / Q000097:blood*; D006801:Humans; D008969:Molecular Sequence Data
chemical_list: D005353:Fibronectins