Application of tyramide signal amplification for detection of N-glycolylneuraminic acid in human hepatocellular carcinoma.
BACKGROUND
N-Acetylneuraminic acid and N-glycolylneuraminic acid (NeuGc) are the most common sialic acids in mammals, and NeuGc has attracted attention as a tumor-associated antigen.


METHODS
In frozen liver sections from patients with hepatocellular carcinoma, glycolipid-type NeuGc was detected on the surface of liver cancer cells in 9 of 17 samples (52.9%) by immunostaining, using two chicken monoclonal antibodies against NeuGc and the tyramide signal amplification method. When conventional immunostaining without amplification was used, all 17 specimens tested were negative.


RESULTS
Increased serum levels of anti-NeuGc IgG and/or IgM were observed in 13 of the 17 patients with hepatocellular carcinoma (76.5%). The presence of these antibodies was mostly attributed to the expression of NeuGc on hepatocellular carcinoma cells. Of the subjects with small HCCs (diameter 3 cm or less), 6 of 10 were positive for serum anti-NeuGc antibodies; however, 1 of these was negative for both serum Alpha-fetoprotein (AFP) and for prothrombin-induced vitamin K antagonist II (PIVKA-II). There was no correlation between serum AFP- or PIVKA-II, levels and the presence of NeuGc or anti-NeuGc IgG and/or IgM.


CONCLUSIONS
The tyramide signal amplification method is useful for the immunohistochemical detection of low-level NeuGc expression by hepatocellular carcinoma cells. We therefore consider that measurement of serum levels of anti-NeuGc antibodies is clinically meaningful and that anti-NeuGc antibody may be a useful screening test, in combination with AFP and PIVKA-II, for the early diagnosis of hepatocellular carcinoma.
Institute for Clinical Research, National Kure Medical Center, 737-0023, Hiroshima, Kure, Japan. t-koda@kure-nh.go.jp
Tetsuzo
T
Koda
Masayoshi
M
Aosasa
Hideyuki
H
Asaoka
Hiroyuki
H
Nakaba
Haruo
H
Matsuda
D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001710:Biotin / Q000031:analogs & derivatives*; D006528:Carcinoma, Hepatocellular / Q000737:chemistry / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000737:chemistry / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009438:Neuraminic Acids / Q000032:analysis* / Q000276:immunology; D014439:Tyramine / Q000031:analogs & derivatives*
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D009438:Neuraminic Acids; C111551:biotinyltyramide; C032592:N-glycolylneuraminic acid; D001710:Biotin; D014439:Tyramine