title: Serum total gangliosides and TA90-IC levels: novel immunologic markers in colorectal cancer.
abstract: BACKGROUND
  Because of the challenge in defining prognostic markers predictive of recurrence or progression, carcinoembryonic antigen (CEA) remains the most frequently used marker in colorectal cancer, despite its low sensitivity. We hypothesized that TA90-IC status and serum ganglioside levels might be useful markers and might be of prognostic significance in colorectal cancer.
  
  
  METHODS
  Serum samples from 68 patients undergoing surgical treatment for histologically proven colorectal cancer were analyzed for the presence of CEA, serum gangliosides, and TA90-IC. Forty-one patients had node-negative disease, whereas 27 patients had limited metastatic disease. The intent was curative resection, even for patients with metastatic disease. Cryopreserved serum specimens were analyzed in a blinded fashion for total serum ganglioside levels (by an assay that detects lipid-associated sialic acids), for CEA, and for TA90-IC (by a murine monoclonal antibody-based enzyme-linked immunosorbent assay). A positive value for TA90-IC levels was defined as an optical density (OD) of more than 0.410 at 405 nm.
  
  
  RESULTS
  Serum ganglioside levels were elevated more frequently than CEA concentrations (84% vs 44%). The combination of serum ganglioside and CEA values was more sensitive (88%) than CEA value alone (44%) in identifying patients with early-stage colorectal cancer. TA90-IC levels were elevated more frequently than CEA concentrations (56% vs 32%). The combination of TA90-IC and CEA values was more sensitive (72%) than CEA value alone (32%) in identifying patients with advanced-stage colorectal cancer. At an enzyme-linked immunosorbent assay cutoff level of 0.410, 15 (56%) patients had positive TA90-IC values. Fourteen patients alive with residual disease had a median OD TA90-IC level of 0.879, and only three patients had levels below the OD cutoff value of 0.410. Thirteen patients with no evidence of disease had a median level of 0.277, and only four patients had OD levels > or = 0.410. TA90-IC was significantly higher in the alive with residual disease patients than those rendered no evidence of disease (P = 0.02).
  
  
  CONCLUSIONS
  We speculate that a multiple-marker analysis that combines CEA values with serum ganglioside and TA90-IC values may be more sensitive than CEA value alone for detecting colorectal cancer. The potential prognostic significance of TA90-IC status in advanced disease warrants further investigation.
authors.affiliation: Laboratory of Glyco-Immunotherapy, John Wayne Cancer Institute, Santa Monica, California 90404-23023, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Perez
authors.forename: Mepur H
authors.initials: MH
authors.lastname: Ravindranath
authors.forename: Rishab K
authors.initials: RK
authors.lastname: Gupta
authors.forename: Rob A E M
authors.initials: RA
authors.lastname: Tollenaar
authors.forename: Cornelius J
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Wood
authors.forename: Daniel
authors.initials: D
authors.lastname: Soh
authors.forename: Donald L
authors.initials: DL
authors.lastname: Morton
authors.forename: Anton J
authors.initials: AJ
authors.lastname: Bilchik
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D003110:Colonic Neoplasms / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005732:Gangliosides / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000097:blood* / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D005732:Gangliosides; C113885:TA90 immune complex