Australia antigen in Singapore Chinese patients with hepatocellular carcinoma and comparison groups: influence of technique sensitivity on differential frequencies

Historical review of the causes of cancer

In the early 1900s, numerous seminal publications reported that high rates of cancer occurred in certain occupations. During this period, work with infectious agents produced only meager results which seemed irrelevant to humans. Then in the 1980s ground breaking evidence began to emerge that a variety of viruses also cause cancer in humans. There is now sufficient evidence of carcinogenicity in humans for human T-cell lymphotrophic virus, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, human papillomavirus, Epstein-Barr virus, and human herpes virus 8 according to the International Agency for Research on Cancer (IARC). Many other causes of cancer have also been identified by the IARC, which include: Sunlight, tobacco, pharmaceuticals, hormones, alcohol, parasites, fungi, bacteria, salted fish, wood dust, and herbs. The World Cancer Research Fund and the American Institute for Cancer Research have determined additional causes of cancer, which include beta carotene, red meat, processed meats, low fibre diets, not breast feeding, obesity, increased adult height and sedentary lifestyles. In brief, a historical review of the discoveries of the causes of human cancer is presented with extended discussions of the difficulties encountered in identifying viral causes of cancer.

The progression of hepatitis B- and C-infections to chronic liver disease and hepatocellular carcinoma: epidemiology and pathogenesis

HCC is a major problem in certain regions of the world, and an increasing problem in the United States. Although the precise mechanisms are not delineated, chronic viral hepatitis B and C clearly cause HCC. Epidemiologic evidence provides strong associations with both viral infections. The predominant pathway to HCC is through cirrhosis, but direct viral carcinogenic effects may also contribute, particularly for hepatitis B. Understanding of this epidemiology and pathophysiology provides the basis for the clinical evaluation, diagnosis, screening, and treatment of HCC.

Molecular biology of hepatocellular carcinoma and hepatitis B virus association

The involvement of the hepatitis B virus in the pathogenesis of hepatocellular carcinoma was initially suggested on the basis of epidemiological studies. In recent years several kinds of experimental evidence have supported this hypothesis; however, the role played by hepatitis B virus in hepatocarcinogenesis still needs to be elucidated. Several groups of researchers are presently involved in establishing whether hepatitis B virus makes a specific genetic contribution to carcinogenesis or predisposes to neoplastic transformation by causing chronic inflammation and cell regeneration. A comprehensive examination of the data available in the literature suggests that the two hypotheses may not be mutually exclusive.

Hepatitis B virus markers and antibodies to hepatitis C virus in Japanese patients with hepatocellular carcinoma

Sera from Japanese patients with chronic liver disease were tested for hepatitis B virus (HBV) markers and antibodies to hepatitis C virus (anti-HCV), and the results were correlated to the presence of hepatocellular carcinoma. In chronic non-A, non-B liver disease, anti-HCV prevalence was high both in patients with hepatocellular carcinoma (78/89, 88%) and without it (66/84, 79%), while previous HBV infection was more common in patients with hepatocellular carcinoma (65/89, 73%) than in those without it (46/84, 55%) (P less than 0.05). Coexistence of anti-HCV and antibodies to HBV was observed frequently in patients with hepatocellular carcinoma (56/89, 63%) compared with patients without it (39/84, 46%) (P less than 0.05). In chronic HBV carriers, anti-HCV was more common in patients with hepatocellular carcinoma (12/38, 32%) than in those without it (3/62, 5%) (P less than 0.01). These results suggest that infection with the two viruses may be a risk factor for more serious liver disease.

Relationship between hepatitis B surface antigen prevalence, per capita alcohol consumption and primary liver cancer death rate in 30 countries

The relationships between the prevalence of hepatitis B surface antigen (HBsAg), mean annual per capita alcohol consumption and primary liver cancer (PLC) death rates were explored in 30 countries. HBsAg prevalence was associated, significantly, with the logarithm of the primary liver cancer death rate (simple correlation coefficient = 0.44, p less than 0.05). This significant association increased following adjustment for a country's mean annual per capita alcohol consumption (partial correlation coefficient = 0.53, p less than 0.01). A logarithmic linear relationship was also found between per capita alcohol consumption and the primary liver cancer death rate after adjustment for the country's prevalence of HBsAg (partial correlation coefficient = 0.38, p less than 0.05). Results from both correlation and regression analyses showed that prevalence of HBsAg was more significantly associated with PLC death rates than was alcohol consumption. However, these two variables were independently related to the PLC death rate in a stepwise multiple regression model. We could not demonstrate an interaction between the two variables. These findings are consistent with the prevailing view that chronic hepatitis B infection is the major factor in the most common form of primary liver cell cancer, hepatocellular carcinoma. In addition, they support the notion that alcohol consumption contributes significantly and independently, although probably to a lesser extent than hepatitis B, to deaths from that disease.

Etiology of human liver cancer: controlled prospective study in liver cirrhosis

The incidence of primary liver cell carcinoma was investigated in a prospective study over 6 yr and 5 mo in 403 clinically unselected patients derived from a homogeneous population by means of serial determination of alpha 1-fetoprotein (AFP) by radioimmunoassay. The diagnosis of liver cirrhosis was proved in 90% by laparoscopy and/or histology and/or autopsy. The incidence of primary liver cell carcinoma in liver cirrhosis in the clinically studied patients was 4.47%, significantly lower than in the autopsy material (11.03%; p less than or equal to 0.025). In the follow-up study, all patients with increasing AFP concentrations exhibited a primary liver cell carcinoma. A transitory rise of AFP (higher than 50 ng/ml) was observed in 15.1% of patients with liver cirrhosis without primary liver cell cancer. In contrast to the results of animal experiments, this transitory rise of AFP was not followed by malignant transformation of the cirrhotic tissue. Posthepatitic liver cirrhosis was observed in 21.57%, postalcoholic liver cirrhosis in 42.93%, and cryptogenic liver cirrhosis in 27.30%. Liver cirrhosis of other etiology occurred in 8.19%. The incidences of primary liver cell cancer in these 4 groups were 4.94, 4.62, 5.45, and 0%, respectively. These differences are not statistically significant, although in absolute figures postalcoholic liver cirrhosis is the main cause of primary liver cell carcinoma in this sample from West Germany. HBs antigen-positive liver cirrhosis was more often associated with primary liver cell cancer than HBs antigen-negative liver cirrhosis (6.58 versus 3.96%); this difference also is not statistically significant. Observations of larger groups of patients may show a higher risk of developing primary liver cell carcinoma in those with a combination of alcohol abuse and HBs antigenemia and/or acute hepatitis in the history. Patients without these 2 risk factors had an incidence of primary liver cell carcinoma of 2.61%; those with 1 risk factor, 5.77%; and those with both risk factors, 10.71%.

Pathology of primary liver cancer

After a brief survey of the factors that play a role in the etiopathogenesis of human hepatocellular carcinomas, a detailed description is given of the macroscopic and microscopic features of human liver cancers as well as their association with cirrhosis. The ultrastructural features of liver cancers of various degrees of differentiation are described. The mode of spread, metastasis formation of primary liver cancers, and most frequent causes of death of liver cancer patients are reviewed.

Clinical aspects of intrahepatic bile duct carcinoma including hilar carcinoma: a study of 57 autopsy-proven cases

The clinical features of 57 autopsied cases of intrahepatic bile duct carcinoma including 28 cases of the peripheral type (cholangiocarcinoma in the narrow sense) and 29 cases of the hilar type are described in comparison with those of hepatocellular carcinoma, with a review of the literature on the clinicopathological aspects of intrahepatic bile duct carcinoma. As compared with hepatocellular carcinoma, the average age of the patients was older; the male predominance was not obvious, chronic parenchymal liver disease was infrequent in the past history, association of primary cirrhosis was seldom, cholestatic features were frequently the early signs and more pronounced during the course, the liver was enlarged to a lesser extent, ascites was less common, signs of portal hypertension were absent or minimal, and extrahepatic metastases were less frequent. In many respects, the hilar type resembled extrahepatic bile duct carcinoma, and the peripheral type was somewhat between it and hepatocellular carcinoma. Although the overall survival was not much different from that for hepatocellular carcinoma, early diagnosis is emphasized; this would make surgical management possible. Differential diagnosis from hepatocellular carcinoma may be possible in the majority with direct cholangiography, liver scan, celiac angiography, determination of alpha-fetoprotein and hepatitis B antigen, and blood chemistry such as SGOT, SLDH, serum bilirubin and alkaline phosphatase. Illustrative cases are given including one patient with a hilar carcinoma who survived for more than 2 years after transhepatic biliary drainage.

Serological evidence of hepatitis B infection in patients with chronic liver diseases: radioimmunoassay of HBsAg and anti-HBs

The prevalence of hepatitis B surface antigen (HBsAg) and anti-HBs was determined by a sensitive double-antibody radio-immunoassay technique in a series of patients with chronic liver diseases. HBsAg was demonstrated in 37 out of 98 consecutive patients with chronic hepatitis (38%) and in 14 out of 108 patients with non-alcoholic cirrhosis (13%). HBsAg was not found in any of the patients with steatosis, alcoholic cirrhosis, or primary biliary cirrhosis. In the patients with chronic hepatitis HBsAg or anti-HBs was demonstrated in 83% of the patients below 40 years of age in contrast to 48% of the patients more than 40 years of age. It is concluded that a substantial part of the patients with chronic hepatitis has serological evidence of actual or past hepatitis B virus infection. This is in contrast to the groups of patients with other chronic liver diseases.

Hepatitis-B: a review

The recent literature on various aspects of hepatitis-B is reviewed with emphasis on the interrelationships of viral structure, antigenic components, and host immune response in acute, chronic, and asymptomatic carrier states of the infection. The mode of replication and mechanisms of transmission are discussed. Special attention is paid to potential non-parenteral routes of spread. The role of hepatitis-B in associated immune complex diseases and in hepatoma is outlined. A guide to the interpretation of serologic tests for hepatitis-B associated antigen and antibody patterns is presented in relation to the clinical stage and prognosis of the infection. Therapy, except in conceptual terms, is not covered but a summary of the current status of active and passive immunization is given. The unresolved question of the infectivity of carrier medical staff for their patient contacts, and the reverse, is discussed.

A case/control study of the association between primary liver cancer and hepatitis B infection in Senegal

A case/control study has been carried out to determine by radioimmunoassay and passive hemagglutination techniques the prevalence of hepatitis B surface antigen (HBsAg) and antibody (anti-HBs) in patients with primary liver cancer (PLC) and age/sex-matched hospital controls with cancers of other sites (OCC) and similarly matched controls without cancer (NCC). HBsAg was found in 61.2% of 165 cases of PLC as compared to 11.7% of 328 NCC. The frequency of HBsAg in PLC patients was significantly higher (72.2%) in those with detectable alpha fetoprotein as compared to those without (40.3%). There was no difference in the frequency of HBsAg in PLC patients with and without accompanying cirrhosis. No significant difference in potential hepatitis exposure history was found in the three study groups.

Immunodeficiency to hepatitis B virus infection and genetic susceptibility to development of hepatocellular carcinoma

The high frequency of hepatitis B antigen (HBsAg) in hepatocellular carcinoma (HCC) patients has led to the hypothesis that immunoresponsiveness to hepatitis B virus (HBV) may be deficient in some patients, and that the immune response deficiency may have a genetic basis. Radioelectrocomplexing (REC), a radioimmunoassay in gel based on the principle of counterimmunoelectrophoresis (CIE), has been used to identify four HBV immune status subgroups: 1) HBsAg +ve/HBsAb +ve; 2) HBsAg +ve/HBsAb -ve; 3) HBsAb -ve/HBsAb +ve; 4) HBsAg -ve/HBsAb -ve/HBsAb -ve. These subgroups comprise 2, 6, 70, and 22 percent, respectively, among blood donors, and 32, 19, 23, and 26 percent, respectively, among HCC patients. Although the HBV exposure rates in the two groups were similar, the immune complexemic rates and HBs antigenemic rates were significantly higher in HBB patients than in the blood donors. It is proposed that the failure of termination of HBV infection revealed by these high rates reflects an immunodeficiency state characterized by an inability to produce high-avidity HBsAb. The immunodeficiency might have a primary genetic basis, or it might be secondary to the immunodepressive effects of concurrent viral or parasitic infections.

[Carcinofetal antigens. I. alpha-fetoprotein (author's transl)]

Alpha-fetoprotein (AFP) is an alpha1-glycoprotein (M.W. about 65000) appearing in the fetal serum of most mammals including man during the early stages of pregnancy; 4 weeks after birth it disappears altogether or exists at very low concentrations as in the normal adult. AFP is formed in the yolk sac, the fetal liver and the gastro-intestinal tract. One of its physiological functions in fetal life is supposed to be the protection of the fetus from maternal oestrogens (oestrophilic property). The clinical significance of AFP is based on the regular and increasing production in primary liver cell carcinoma, less frequently in teratogenetic tumors where it serves as a control of therapy and course of the disease. Less frequent, minor and temporary increases in the AFP serum level occur in several primary tumors with secondary liver involvement, and in inflammatory gastro-intestinal diseases, e.g. of the liver (hepatitis, cirrhosis). AFP has an increasing importance in gynecology (gestational age, fetal distress syndrom, malformations, hydatidiform mole/chorion carcinoma). The physico-chemical properties of AFP are widely known. Both fetal and tumor AFP appear to be immunologically and biochemically identical, as are that of tissue and biological fluids. The differences observed (variants, microheterogeneity) depend mainly on the different content of sialic acid. An antigenetic relationship exists, between the AFP of most species. The immunodiffusion (Ouchterlony) is the most frequently used but relatively insensitive test (1-5 mug/ml) in finding AFP, whereas the radioimmunoassay is the most sensitive one (up to 0,25 ng/ml) and permits the determination of normal serum levels in adults (below 20 ng/ml). The serum concentration in healthy pregnant women lies up to 500 ng/ml, in patients with hepatitis, liver cirrhosis and other liver diseases mostly under 3 mug/ml, whereas in those with primary liver cell carcinoma levels up to and above 600 mg-percent have been found.