Correlation between alpha(1)-acid glycoprotein and total sialic acid in serum from dogs with tumours

The influence of the acute phase protein alpha(1)-acid glycoprotein (AGP) o n the concentration of total sialic add (TSA) in serum was investigated by assessing their degree of correlation in 115 clinically healthy dogs, 29 do gs with malignant mammary tumours, 12 dogs with various other malignant tum ours, 12 dogs with benign mammary tumours and 10 dogs with various other be nign tumours. Serum from dogs with malignant mammary tumours and other mali gnant tumours had a statistically significant correlation between AGP and T SA concentrations (Spearman correlation coefficient (r(s)) = 0.52, P = 0.00 05, n = 41). The correlation was also statistically significant in dogs wit h benign mammary rumours and other benign tumours (r(s) = 0.48, P = 0.02, n = 22). The Spearman correlation coefficient was 0.51 (P = 0.0001, n = 63) in all dogs with tumours. This was also the case if only those dogs with le vels of AGP comparable to healthy dogs (< 750 mg/l) were included in the an alysis (r(s) = 0.42, P = 0.01, n = 56). In clinically healthy dogs, the cor relation was not statistically significant (r(s) = 0.17, P = 0.07, n = 115) . None of the four groups of dogs with rumours had changed serum AGP concen trations compared to clinically healthy dogs (all t-tests gave P values abo ve 0.05). The serum concentrations of AGP did not correlate with the clinic al stage of dogs with mammary tumours. In conclusion, AGP and TSA concentra tions in serum are positively correlated in dogs with tumours, partially ex plaining the increase in serum TSA in these dogs. Increased sialylation of the AGP molecule in dogs with tumours might contribute to the increased ser um TSA levels.