Detection of serum α-fetoprotein in dogs with hepatic tumors

Abstract

Summary Serum α-fetoprotein (afp) concentration was detected by use of 2 commercially available kits containing antibodies to human afp—a radioimmunoassay and an enzymetric test. Using neonatal canine serum (a source high in afp), it was determined that reagents from both kits were able to bind to canine afp, but a significant difference was detected in afp concentration. The enzymetric test was superior in detecting canine afp. Sera from dogs were classified into 6 groups: from dogs with primary hepatic tumors only (group 1); from dogs with primary hepatic tumors and other tumors (group 2); from dogs with normal liver but with other types of neoplasia (group 3); from dogs with nonneoplastic hepatic disease and tumors originating in other organs (group 4); from dogs with nonneoplastic hepatic disease only (group 5); and from clinically normal dogs (group 6). Serum biochemical determinations (alkaline phosphatase, alanine transaminase, albumin, total protein, total bilirubin, and serum bile acids) and values from the 2 afp assays were obtained for all dogs. Serum afp concentration detected by the enzymetric test was significantly higher in dogs with hepatocellular carcinoma and cholangiocarcinoma. Values > 250 ng/ml were detected in 5 of 9 dogs with cholangiocarcinoma and in 3 of 4 dogs with hepatocellular carcinoma. High serum afp concentration also was indicative of liver involvement in 2 of 3 dogs with primary hepatic lymphosarcoma; 2 dogs had values > 225 ng/ml. Serum afp concentration in dogs with other types of hepatic tumors was < 250 ng/ml, and serum afp concentration could not be correlated with such tumors. Discriminatory analysis was done to determine which serum biochemical values best aided differentiation of hepatic neoplasia from nonneoplastic hepatic disease. Along with high serum afp concentration, high serum alkaline phosphatase activity and low albumin concentration were the most important analytes. If hepatic tumor is suspected, we recommend use of the enzymetric test to determine afp concentration, in addition to use of serum biochemical values, clinical findings, and radiography, to aid in the diagnosis.