Does hepatitis B virus infection cause breast cancer?

Abstract

Lifestyle and family history are two of the most important risk factors for breast cancer (BC). However, these risk factors cannot explain the differences in the incidence and early BC onset among Chinese females compared to their western counterparts. We propose in this hypothesis the potential mechanism of indirect oncogenesis of hepatitis B virus (HBV) in causing BC through its persistence as occult infection and continuous replication with long term subtle liver damage. Estrogen is mainly deactivated in the liver and long term necro-inflammatory damage to liver may result in persistent high level of estrogen, which is a dominant risk factor for BC. HBV may also directly affect the breast cells through its cis and trans effects of HBx which may act as oncoprotein. Given the recognised aetiologic association between oestrogen and breast cancer risk, there is biological plausibility that dietary soy and vegetable intake which is rich in the Chinese diet may have anti-carcinogenic effect on the breast. The seemingly conflicting phenomenon of early age onset and lower BC incidence in China might be due to wide imbalance in the amount of exposure to carcinogenic factor (e.g., HBV infection) for decades and the carcinoprotective exposure levels (e.g., isoflavonoids and flavonoids intake). For example, the increase in carcinoprotective levels would lead to lower incidence of breast cancer and vice versa. Although the focus of this personal view is on HBV, this by no means negates the roles of other known risk factors in breast-cancer development. Characterisation of the role of HBV in BC could potentially benefit Chinese females by decreasing incidence and increasing overall survival.

A nomogram based on clinicopathological features and serological indicators predicting breast pathologic complete response of neoadjuvant chemotherapy in breast cancer

“…The mechanism of hepatitis B virus (HBV) and breast cancer progression and prognosis is unclear, but reports have shown that HBV infection is a risk factor for breast cancer 50 . The mechanism may be related to the interference of hepatitis B virus X protein (HBx) on cell repair mechanism, which leads to cell carcinogenesis 51 . In addition, HBV infection causes liver dysfunction, which affects estrogen regulation, and estrogen is a known risk factor for breast cancer.…”

Prognostic value of chronic hepatitis B virus infection in patients with breast cancer in a hepatitis B virus endemic area

“…This may explain to some extent that the observation of chronic HBV infection in this study mainly affects the prognosis of luminal BC, rather than other subtypes. Secondly, HBV may also directly affect breast cells through the action of oncoprotein HBV X protein (HBX) (21)(22)(23). For example, several studies have found that BC tissue highly expresses the oncoprotein HBXIP, a protein that interacts with HBX (24).…”

Substitution of the CD81 Binding Site and β-Sandwich Area in E2 of HCV in Cambodia

“…Genotype 1b is the most common globally (46%) [2], whereas genotype 6 is predominant in Southeast Asia [6]. In fact, the distribution of HCV genotypes is closely related to the pathway of virus transmission and human migration [7]. Therefore, the characterization of HCV genotypes correlates with both clinical features (natural history and therapy) and epidemiology [8].…”