Antibodies to tumor-associated carbohydrate epitopes in sera of cancer patients and blood donors

Enzyme-linked immunosorbent assay was applied for determination of antibodi es to tumor-associated carbohydrate epitopes in serum of gastrointestinal a nd breast cancer patients and in blood donors. The synthetic polyacrylamide (PAA) conjugates with Thomsen-Friedenreich epitope (TF), TF-precursor (Tn) , Gal alphai-3Gal beta (alpha Gal), SiaTn, and SiaLe(a) were used in the as say. Tris-PAA was used as a negative control. A significantly lower anti-TF and anti-Tn IgG levels were observed in gastric cancer patients in compari son with donors. In colorectal cancer patients a significantly lower anti-T F IgG levels were observed as well. In combined group of gastric and colore ctal cancer patients at stage I of the disease a significantly lower anti-T F and anti-Tn IgG levels in comparison with donors were observed. Levels of anti-Tn IgG were significantly lower in donors with A blood-group phenotyp e than in B group. Anti-SiaTn and anti-SiaLe(n) IgG antibodies in sera were revealed rarely. The negative correlation between anti-SiaLe(n) IgG and CA 19-9 levels in serum of gastrointestinal cancer patients was observed: r = -0.4377, P = 0.047. Thus, gastrointestinal carcinoma is associated with lo w level of serum anti-TF IgG antibodies.