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Qu et al. Etiological prevention of liver cancer

INTRODUCTION (0.43%) [9,10] . The seroprevalence of HBV and/or HCV
serological markers among the liver cancer patients
Primary liver cancer (PLC) is one of leading causes from these regions is helpful to understand the impact of
of cancer deaths in China. Worldwide, hepatocellular HBV and/or HCV on this disease in China.
carcinoma (HCC) represents the major histological
type of liver cancer and likely accounts for 70-85% of The study by Wang et al. reported that 83.9% of liver
[8]
cases, followed by intrahepatic cholangiocarcinoma cancer patients with histological confirmation were
(iCCA) which accounts for approximately 10-25% of HCC and 11.0% were iCCA. Among the 1,823 HCC
all hepatobiliary malignancies . Other risk factors for patients, 1,567 (86.0%) cases had HBV markers alone,
[1]
PLC include exposure to aflatoxin, algal hepatotoxins indicated by HBsAg(-)/(+) & anti-HBc(+). Remarkably,
in drinking water, betel nut chewing, diabetes mellitus, 18.2% of them were HBsAg(-) & anti-HBc(+) and serum
alcohol consumption, and tobacco use . Approximately HBV-DNA positive. HCV infection alone, indicated by
[2]
80% of HCC worldwide was estimated to be associated presence of anti-HCV(+), was found in 2.5% of HCC
with chronic infections with hepatitis B virus (HBV) and cases, and HBV & HCV co-infection were found in
hepatitis C virus (HCV) . Some studies also found the 6.7% of HCC cases. Altogether, the contribution of HBV
[3]
relationship between iCCA and HBV or HCV , although infection to HCC was at least 85-90% . This study
[4]
[8]
their causal effects need to be further confirmed. indicated that the contribution of HBV infection to HCC
in China had been under-estimated previously, most
The contribution of HBV or HCV to HCC differs in probably due to the unrecognized status of occult HBV
different geographical areas, mainly due to the varied infection among the HBsAg-negative HCC cases. The
prevalence of HBV or HCV in different populations [1,3] . role of chronic HBV infection in HCC in China is clearly
A meta-analysis including 39 studies in China from dominant. Therefore, controlling chronic HBV infection
1954 to 2010, based on the seroprevalence of hepatitis is crucial for reducing the risk of liver cancer, particularly
B surface antigen (HBsAg), and/or antibodies against HCC.
HCV (anti-HCV) in HCC patients, reported that about
70% of HCC was associated with HBV infection alone, Although some perinatal infections from maternal
5% with HCV infection alone, and 6% with HBV & HCV HBV transmission may cause fulminant hepatitis in
co-infection. The analysis also suggested that around infancy , a fatal disease of acute hepatocyte necrosis
[11]
19% of HCC was unrelated to HBV or HCV . leading to hepatic encephalopathy and coagulopathy,
[3]
HBV infection in infancy or early childhood leads to a
HBV occult infection, which is indicated by undetectable high rate of persistent infection [12] . It was reported that
serum HBsAg and low level of serum HBV DNA among infected neonates born to mothers with positive
(sometimes HBV was detected only in the liver), has hepatitis B e antigen (HBeAg), the chronicity of HBV
been frequently reported in different liver diseases [5,6] . infection was 80-90% [12] . Of children infected before 6
In recent years, a substantial HBsAg-negative HCC years of age, chronic infection was reported to develop
patients were found to be serum HBV-DNA positive by in approximately 30% [13,14] . It had been documented that
using nucleic acid testing . To understand the impact the majority of persons with chronic HBV infection in
[7]
of HBV and/or HCV on PLC, Wang et al. in National China acquired it at birth or in early childhood [15] .
[8]
Cancer Center of China recently analyzed a total of 2,172
liver cancer cases, which were confirmed by histology. Long-term major adverse outcomes of chronic HBV
In this report, a total of 5,988 patients with PLC were infection are liver cancer and cirrhosis. Longitudinal
identified from Northern regions of China (from January studies of untreated persons with chronic HBV infection
1, 2003 to December 31, 2014) based on clinical showed that there is about 8-20% of cumulative risk
diagnosis criteria. The analysis found no differences in of developing cirrhosis over five years. In those with
the distributions of age, gender, ethnicity, and serological cirrhosis, there is an approximately 20% annual risk
virus markers between the cases with and the cases of hepatic decompensation and the annual incidence
without histological confirmation. Therefore, the of HCC could be as high as to 5% [16] . Therefore, it is
proportion of HBV and/or HCV markers among the 2,172 important to reduce the risk of liver cancer beginning
histologically confirmed liver cancer cases could well at birth or in early childhood by preventing chronic HBV
represent the general cases . Although the data were infection.
[8]
from one single medical center, the patients in this study
were from diverse regions throughout all the provinces Brief history of HBV vaccination program and
in the Northern regions of China. HBsAg seroprevalence its effect in reducing HBsAg seroprevalence
was 4-6% in the Northern regions, lower than that of the in China
overall population (7.18%), while anti-HCV prevalence The relationship of chronic HBV infection and HCC
was 0.53%, higher than that of the overall population development was well established based on a

Hepatoma Research ¦ Volume 3 ¦ October 25, 2017 229