Osamu Isokawa

The fucosylation index of α-fetoprotein as a possible prognostic indicator for patients with hepatocellular carcinoma

The aim of this study was to elucidate the usefulness of measuring the fucosylation index (FI) of α‐fetoprotein (AFP) before the initiation of therapy as a new prognostic indicator for patients with hepatocellular carcinoma (HCC).

Microheterogeneity of serum transferrin in the diagnosis of hepatocellular carcinoma

Heterogeneous reactivity of human serum transferrin (Tf) with lectins was analysed using patient sera to determine whether it can be used to distinguish patients with hepatocellular carcinoma (HCC) from those with liver cirrhosis (LC). Microheterogeneity of Tf was analysed by crossed immunoaffinity electrophoresis (CIAE) with concanavalin A (Con A) and Lens culinaris agglutinin (LCA). Sample sera from 58 patients with HCC, 43 patients with LC and 10 normal controls were used in this study and the results were evaluated statistically. The increments of Con A‐non‐reactive (C1) and ‐weakly reactive (C2) species of Tf were observed in HCC compared with those of LC and Norm. Significant increase in the combined percentage of Con A‐ C1 + C2 species was also revealed in HCC (35.5 ± 8.5%, mean ± s.d.) compared with those of LC (29.1 ± 6.8%; P < 0.001) and normal controls (17.1 ± 2.3%; P < 0.001). The elevation of LCA‐reactive (L2) species of Tf was recognized in HCC (8.2 ± 3.8%) in comparison with those of LC (4.8 ± 3.1%; P<0.001) and normal controls (1.3 ± 1.7%; P < 0.001). The increment of C1+C2 species and/or L2 species of Tf was observed in 78% (sensitivity) of patients with HCC. The specificity, the positive predictive value and the overall accuracy were 81, 88 and 72%, respectively. Positive ratio of C1+C2 and/or L2 species was 77 and 70% in alpha‐fetoprotein low and ‐high producing HCC patients, respectively. These results indicate that the microheterogeneity analysis of human serum Tf is useful for distinguishing patients with HCC from those with LC and normal controls.

Alpha-fetoprotein-producing renal cell carcinoma with increased activity of N-acetylglucosaminyl-transferase III.

N-acetylglucosaminyltransferase (GnT) III catalyzes the addition of N-acetylglucosamine through a beta 1-4 linkage to the mannose of the trimannosyl core, resulting in conversion of the concanavalin-A-(ConA)-reactive glycan into the ConA-nonreactive one. In this study, we measured GnT III levels in serum, tumor, and surrounding normal tissues together with a glucosaminylation index of alpha-fetoprotein (AFP), which is defined as the percentage of the ConA-nonreactive species in total AFP, in a case of AFP-producing renal cell carcinoma. The glucosaminylation index was determined by affinoelectrophoresis in the presence of ConA. GnT III was measured by using a pyridylaminated asialoagalactobiantennary sugar chain as a substrate by high-performance liquid chromatography. The glucosaminylation index of serum AFP, the concentration of which was 68 ng/ml, was 60%. This value is much higher than observed in hepatocellular carcinomas. The tumor tissue level of GnT III was 55.34 pmol/mg/h which was about six fold higher (9.50 pmol/mg/h) than in normal surrounding tissues. The serum level of this enzyme before surgery was 27.65 pmol/ml/h and decreased to 5.38 pmol/ml/h thereafter in association with a depression of serum AFP from 68 to 5.4 ng/ml. Thus, an increased level of GnT III in tumor tissues could account for the elevated conversion of a biantennary complex type sugar chain of AFP into a bisecting glucosaminylated biantennary one resulting from the addition of an N-acetylglucosamine residue at the trimannosyl core. This is, to our knowledge, the first report explaining the change in the carbohydrate structure of AFP with different affinity to ConA on the enzymatic basis in a renal cell carcinoma.

Microheterogeneity analysis of serum transferrin before and after therapies to hepatocellular carcinoma

Abstract The reactivity of transferrin (Tf) with concanavalin A (Con A) was examined by crossed immuno-affinity electrophoresis (CIAE) of the sera from patients with hepatocellular carcinoma (HCC). Serum Tf was separated into three species — Cl (Con A-nonreactive), C2 (-weakly reactive) and C3 (-reactive) —designated consecutively from the anode by CIAE. Nineteen pairs of serum samples were evaluated before and 1 month after therapies for HCC by transcatheter arterial embolization and/or percutaneous ethanol injection, and surgical resection. The significant decrease in the mean percentage of Tf-Cl species was observed after the above therapies, although there was no statistical difference between the serum Tf concentration before and after therapies. Thus, the present study suggests that the measurement of these species would be useful as an index of several therapeutic effects on HCC, especially in the case of α-fetoprotein (AFP) and des-γ-carboxy prothrombin (DCP)-non-producing HCC.

Quantitation of telomerase activity in hepatocellular carcinoma: a possible aid for a prediction of recurrent diseases in the remnant liver

Because telomerase activity is necessary for cell immortality and probably associated with tumor progression, we have evaluated a possible aid for quantitation of the activity to predict intrahepatic recurrences after surgery in patients with hepatocellular carcinoma (HCC). HCC tissues obtained by surgical resection from 20 patients were studied. Telomerase activity was expressed as peaks with a periodicity through a fluorescence-based telomeric repeat amplification protocol using an autosequencer, and the quantity of activity was calculated from peak areas. A ratio of fluorescence intensity depending on telomerase to that of an internal standard was used as a value of relative telomerase activity (RTA). RTA in serially diluted S100 extracts from HepG2 cells was well correlated with the amount of the extracts. The mean RTA value of 36.4 +/- 27.8 (mean +/- SD, 3.21 to 105) in 9 patients suffering from early recurrences after surgery was significantly higher than that (9.84 +/- 7.65; mean +/- SD, 3.00 to 29.0) in 11 patients without intrahepatic recurrences during the early period (P = .004). These results indicate that RTA value can be a useful predictor for intrahepatic recurrences during the early period after surgical resection of HCC.