Serum alpha-L-fucosidase: a new marker for the diagnosis of primary hepatic carcinoma?

Urinary level of L-fucose as a marker of alcoholic liver disease

The urinary levels of L-fucose were measured in 93 alcoholics; 20 of these were without liver disease, 57 with noncirrhotic alcoholic liver disease, and 16 with alcoholic liver cirrhosis. In addition, patients with cirrhosis due to viral infection, and healthy subjects were evaluated. The mean urinary L-fucose concentration showed significantly higher values in patients with alcoholic liver disease and alcoholic liver cirrhosis when compared with the healthy subjects or the chronic alcoholics without liver disease (p < 0.001). The urinary L-fucose level was also significantly higher (p < 0.001) in cases of alcoholic liver cirrhosis than in noncirrhotic alcoholic liver disease (384 +/- 97 vs. 240 +/- 95 mumol/g of creatinine). No difference was observed between the healthy subjects and chronic alcoholics without liver disease (143 +/- 29 vs. 155 +/- 60 mumol/g of creatinine). The urinary level of L-fucose was significantly higher with alcoholic cirrhosis (384 +/- 97 mumol/g of creatinine) than with viral cirrhosis (265 +/- 42 mumol/g of creatinine) (p < 0.001). The measurement of urinary L-fucose may be a useful marker of alcoholic liver disease.

Serum alpha-L-fucosidase. A useful marker in the diagnosis of hepatocellular carcinoma

BACKGROUND AND METHODS

The value of serum alpha-L-fucosidase activity in the diagnosis of hepatocellular carcinoma (HCC) was investigated by determining the enzyme activity levels in 21 patients with HCC, 76 patients with cirrhosis, 22 patients with other malignant neoplasms, and 23 healthy subjects.

RESULTS

The serum alpha-L-fucosidase activity level in patients with HCC (575.76 +/- 212.86 nmol/ml/h) was significantly higher than that found in patients with cirrhosis (274.55 +/- 138.97 nmol/ml/h; P less than 0.001) or other neoplasms (257.91 +/- 128.12 nmol/ml/h; P less than 0.001) and in controls (221.23 +/- 114.45 nmol/ml/h; P less than 0.001). No significant differences were found between controls and patients with cirrhosis and between controls and patients with other malignant neoplasms. When 443 nmol/ml/h is taken as the cutoff value (mean value of controls plus 2 standard deviations), alpha-L-fucosidase sensitivity and specificity were 76% and 90.9%, respectively.

CONCLUSIONS

These results suggest that alpha-L-fucosidase is a useful marker for detecting HCC, in conjunction with alpha-fetoprotein and ultrasonography.

Increased plasma cathepsin D concentration in hepatic carcinoma and cirrhosis but not in breast cancer

Using a sandwich enzyme-linked immunoassay, plasma total cathepsin D concentration was assayed in 40 breast cancer patients and 84 patients with various liver diseases and compared to that of 52 normal subjects. There were no significant variations found in breast cancer patients related to tumor size, node invasiveness or metastases. In normal women, cathepsin D levels were slightly but not significantly increased in the luteal phase and in pregnancy. By contrast, plasma cathepsin D concentration was significantly increased in 70-75% of patients with liver disease (cirrhosis, hepatocarcinoma, hepatitis), but not in those with liver steatosis. Cathepsin D was independent of most of the plasma hepatic function tests and was correlated with alpha-fetoprotein in cirrhosis and with alpha-fucosidase in primary hepatocellular carcinoma. We conclude that plasma cathepsin D is not a useful marker in breast cancer. However, since the cellular level of this protease is associated with risk of metastasis in breast cancer, clinical follow-up will be required to test whether high cathepsin D plasma concentration has any prognostic value in liver cirrhosis and primary hepatocarcinoma.

Serum alpha-L-fucosidase. A more sensitive marker for hepatocellular carcinoma?

Forty-nine liver disease patients (7 chronic persistent hepatitis, CPH; 10 chronic active hepatitis, CAH; 13 liver cirrhosis, LC; 9 primary hepatocellular carcinoma, PHC, without LC; and 10 PHC with associated LC) and 20 controls were assessed for their serum alpha-L-fucosidase (ALF) and alpha-fetoprotein (AFP) levels and several routine liver injury parameters. Tumor diameter in those with hepatic cancer was assessed by angio-CT. Only ALF and AFP were significantly greater in patients with PHC and PHC + LC patients as compared to patients with LC alone. At an accepted cutoff level of 500 ng/ml, the AFP level provided 43% false negative tests. On the other hand, an ALF level exceeding 740 mumol/hr/ml provided a sensitivity of 84% with a specificity of 94%. No relationship between the ALF level and Child's criteria or with any liver injury parameter was evident. Considering all individual values, the ALF, rather than the AFP, correlated with tumor size. This finding suggests the ALF level may be of value in the early detection of PHC as well as in the follow-up of patients treated for PHC.

Differential alpha-fetoprotein lectin binding in hepatocellular carcinoma. Diagnostic utility at low serum levels

The reactivity of serum alpha-fetoprotein (AFP) from 20 patients with hepatocellular carcinoma (HCC) with immobilized lentil lectin was examined and found to be significantly greater (39% +/- 18%) than that of the same protein from seven patients with chronic liver disease (CLD, 11.2% +/- 3.3%), seven with fulminant hepatic failure (FHF, 10% +/- 8.4%), and eight normal pregnant women (4.1% +/- 2.7%). The reactivity with Concanavalin A (Con A) was also significantly greater for AFP from HCC patients (44.5% +/- 12.5%) than that from FHF patients (7.7% +/- 4%) and normal pregnant women (5.3% +/- 3.3%), but not from patients with CLD. The reactivity with lentil lectin permitted distinction between those with HCC (31.3% +/- 14.1%) and those with uncomplicated CLD (11.2% +/- 8.4%) even when the absolute levels of serum AFP were in the same range (80-400 ng/ml). Evaluation of the alterations by lectin binding methodology may be useful in overcoming problems associated with distinguishing between malignant and CLD, particularly at moderate serum AFP elevations.

Variations in serum alpha-L-fucosidase activity during childhood and pregnancy

Variations in serum alpha-L-fucosidase activity (AFU) have been studied during childhood and pregnancy. 994 children, ages 1 day to 15 yr, were examined; no sex-linked difference was found, but significant variations according to age were demonstrated. AFU activity rose during the first 10-15 days after birth, remained high during the second month then decreased till the end of the first year, thereafter no significant changes were observed. In pregnancy, AFU activity rose and dropped quickly after delivery; neither hypertension nor fetal distress led to AFU activity changes during pregnancy. Thus, in addition to the great variability of AFU linked to the genetic polymorphism, the physiological factors such as age or pregnancy have to be taken into account to establish the significance of AFU variations in pathological situations.

Alpha-L-fucosidase as a serum marker of hepatocellular carcinoma in southern African blacks

The purpose of this study was to compare alpha-L-fucosidase and alpha-fetoprotein as serum markers of hepatocellular carcinoma in 72 southern African blacks with this tumour and 64 matched patients with benign hepatic diseases which might be mistaken clinically for hepatocellular carcinoma. Alpha-L-fucosidase activity was assayed using p-nitrophenyl-L-fucopyranoside (pNpf) as a substrate and alpha-fetoprotein concentrations were measured by radioimmunoassay. Serum alpha-L-fucosidase activity in the patients with hepatocellular carcinoma (mean 1,268, s.e.m. +/- 83.7, median 1,150 and range 38-3,698 nmol pNpf ml-1 h-1) was significantly higher than that in the matched controls (mean 798, s.e.m. +/- 65.8, median 648 and range 273-3,825 nmol pNpf ml-1 h-1) (P = 0.0001). However, alpha-L-fucosidase was both less sensitive (75 versus 87%) and less specific (70 versus 87%) than alpha-fetoprotein as a serum marker of hepatocellular carcinoma. When, in an endeavour to eliminate false-positive results, the diagnostic cut-off level for alpha-L-fucosidase was increased to 1,500 nmol pNpf ml-1 h-1 and for alpha-fetoprotein to 400 ng ml-1, the sensitivity of alpha-L-fucosidase fell to 21% whereas that of alpha-fetoprotein remained satisfactory at 78%. If the two markers were used together, the number of false-negative alpha-fetoprotein results was reduced from 13 to 5.5%. We conclude that alpha-L-fucosidase is less useful than alpha-fetoprotein as a single marker of hepatocellular carcinoma in southern African blacks. However, the two markers can profitably be used together.

Biochemical aspects of alpha-L-fucosidase in hepatocellular carcinoma

Biochemical characteristics of alpha-L-fucosidase (alpha-L-fucoside hydrolase, EC 3.2.1.51) were studied in tumorous and nontumorous human hepatocellular carcinoma (n = 14). Five parameters were studied: (i) specific activity, (ii) thermostability, (iii) enzyme affinity for an artificial substrate (Km), (iv) isoenzyme patterns of the glycosidase before and after neuraminidase treatment and (v) pH influence on enzyme activity. The specific activity of alpha-L-fucosidase was significantly decreased in tumoral liver when compared to nontumoral liver. The curve of pH activity constantly showed a broad optimum centered near pH 5, whereas two optima were always observed in nontumoral areas. In contrast, there was no modification of the thermostability, the substrate affinity and the isoenzyme patterns of alpha-L-fucosidase in hepatocellular carcinoma.

Malignant cell glycoproteins and glycolipids

The cell surface is involved in cell growth and division, cell-cell interaction, communication, differentiation and migration, and other processes likely to be involved in malignant transformation and/or the metastatic spread of cancer. Although there are many alterations of glycoproteins and glycolipids on the malignant cell surface, it is unclear whether these alterations are epiphenomena or an integral part of the malignancy process. This article reviews the recent literature and some earlier studies relevant for understanding emerging concepts and trends with respect to malignant cell glycoconjugates. Emphasis is on structural alterations of the carbohydrate portions of malignant cell glycoproteins and glycolipids and on the enzymes (glycosyltransferases and glycosidases) involved in their metabolism. Practical applications derived from malignant cell glycoconjugate studies are discussed briefly with respect to the diagnosis, staging, monitoring, and treatment of malignant disease. The review concludes by indicating which research areas on malignant cell glycoconjugates are likely to be fruitful in increasing our basic understanding of, and ability to deal effectively with, malignant disease.

Tumour markers in diagnosis and management

The 20-year period since the discovery of AFP by Abelev has seen the introduction of a wide range of new tumour markers and it is now clear that PLC is biologically heterogeneous. Hepatoblastomas, fibrolamellar carcinomas, hepatocellular carcinomas and cholangiocarcinomas may secrete a variety of distinctive markers which are predominantly glycoproteins, and may resemble those found in placenta or fetal liver. Diagnostically, AFP remains the best marker for HCC, both in sensitivity and specificity; it is known to consist of isoforms. In patients with elevated serum AFP and filling defects on liver scan, Con A reactive AFP may differentiate PLC from hepatic metastases, whilst fucosylated AFP may distinguish PLC from benign disorders when AFP is non-diagnostically elevated. With this recognition of tumour heterogeneity the value of a multiple-marker approach has become apparent. The measurement of vitamin B12 binding protein and neurotensin should lead to the detection of most patients with the fibrolamellar variant of HCC and many of these should be resectable. In patients with normal serum AFP levels, HCC-associated GGTP is of major value whilst in low-incidence areas for HCC, patients should also be screened for H-ALP; using a multiple marker approach in high-risk groups, 90% of clinically diagnosed hepatocellular carcinomas are serologically positive. The Chinese and Alaskan studies, in which small, potentially resectable tumours were detected, suggest that it is now possible to achieve 5-year survival figures of up to 60% in HCC patients detected by screening. The value of such a strategy in low-incidence countries is currently under study. In patient monitoring, as in diagnosis, AFP remains the outstanding marker. In AFP-negative patients, other markers including vitamin B12-binding protein, neurotensin, HCC-specific isoenzymes, des-gamma-carboxy-prothrombin and alpha-fucosidase, are of undoubted diagnostic value, but their value as indicants of disease progression remains to be established. In monitoring the response of hepatic metastases, CEA remains the least unsatisfactory marker but should always be used in conjunction with serial ultrasound scans. Tumour markers now play an important role in the diagnosis and monitoring of PLC but a role is also emerging in tumour imaging and drug targeting. The next 20 years should see the introduction of tumour markers of high sensitivity and specificity which make a fundamental contribution not only to detection and monitoring, but also to the effective treatment of liver cancer.