Do viruses cause breast cancer?

Linking Human Betaretrovirus with Autoimmunity and Liver Disease in Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by the production of diagnostic antimitochondrial antibodies (AMA) reactive to the pyruvate dehydrogenase complex. A human betaretrovirus (HBRV) resembling mouse mammary tumor virus has been characterized in patients with PBC. However, linking the viral infection with the disease is not a straight-forward process because PBC is a complex multifactorial disease influenced by genetic, hormonal, autoimmune, environmental, and other factors. Currently, PBC is assumed to have an autoimmune etiology, but the evidence is lacking to support this conjecture. In this review, we describe different approaches connecting HBRV with PBC. Initially, we used co-cultivation of HBRV with biliary epithelial cells to trigger the PBC-specific phenotype with cell surface expression of cryptic mitochondrial autoantigens linked with antimitochondrial antibody expression. Subsequently, we have derived layers of proof to support the role of betaretrovirus infection in mouse models of autoimmune biliary disease with spontaneous AMA production and in patients with PBC. Using Hill’s criteria, we provide an overview of how betaretrovirus infection may trigger autoimmunity and propagate biliary disease. Ultimately, the demonstration that disease can be cured with antiviral therapy may sway the argument toward an infectious disease etiology in an analogous fashion that was used to link H. pylori with peptic ulcer disease.

Interrelated Oncogenic Viruses and Breast Cancer

Breast Cancer is a multifactorial disease and recent evidence that viruses have a greater role in its aetiology and pathophysiology than previously hypothesized, has garnered a lot of attention in the past couple of years. After the role of Mouse Mammary Tumour Virus (MMTV) in the oncogenesis of breast cancer has been proved in mice, search for similar viruses found quite a plausible relation of Human Papilloma Virus (HPV), Epstein–Barr virus (EBV), and Bovine Leukaemia Virus (BLV) with breast cancer. However, despite practical efforts to provide some clarity in this issue, the evidence that viruses cause breast cancer still remains inconclusive. Therefore, this article aims to clarify some ambiguity and elucidate the correlation of breast cancer and those particular viruses which are found to bring about the development of tumorigenesis by a previous infection or by their own oncogenic ability to manipulate the molecular mechanisms and bypass the immune system of the human body. Although many studies have reported, both, the individual and co-existing presence of HPV, EBV, MMTV, and BLV in patient sample tissues, particularly in Western women, and proposed oncogenic mechanisms, majority of the collective survey of literature fails to provide a delineated and strong conclusive evidence that viruses do, in fact, cause breast cancer. Measures to prevent these viral infections may curb breast cancer cases, especially in the West. More studies are needed to provide a definite conclusion.

Prevalence of mucosal and cutaneous human papillomavirus in Moroccan breast cancer

BACKGROUND

Due to recent technical improvements and some encouraging new results, there has been a resurgence of interest in the possibility that a substantial proportion of breast cancers (BCs) may be caused by viral infections, including Human papillomavirus (HPV). The aim of this study was to determine the prevalence of mucosal and cutaneous HPV in tumours from Moroccan BC patients.

MATERIALS AND METHODS

Frozen tumours from 76 BC cases and 12 controls were evaluated for the presence of 62 HPV-types using highly sensitive assays that combine multiplex polymerase chain reaction and bead-based Luminex technology.

RESULTS

HPV DNA was found in 25.0% of BC tumours and only 8.3% of controls. Beta and gamma HPV types were found in 10.5% and 6.6% of BC tumours, respectively. High-risk mucosal types HPV16 and 18 were not detected in the subjects, but other probable/possible high-risk or high-risk -HPV types (HPV51, 52, 58, 59, and 66) were found in 5.3% of BC tumours. Statistical analysis showed no significant difference between, controls, BC cases and the inflammatory status (p > 0.05).

CONCLUSION

HPV DNA was found 3 times as frequently in the BC tumours as in the controls. However, this difference requires confirmation in a larger sample.

Is Human Papilloma Virus Associated with Breast Cancer? A Review of the Molecular Evidence

BACKGROUND

Although the association of human papillomavirus (HPV) with many cancers is well established, the involvement of HPV in breast cancer remains controversial. The purpose of this study is to perform a comprehensive review of the results and methods used to demonstrate that HPV markers are present in human breast cancer, and how well these studies fulfil the criteria for proving the viral etiology of a cancer.

STUDY DESIGN

We conducted a search for molecular studies published until November 2016 that relate human breast cancer to HPV.

RESULTS

Forty-three original molecular studies were found, some of which compared cases to nonneoplastic controls. Some investigations did not identify HPV in mammary tissue, but others identified it with different frequencies of positivity, varying between 1.2 and 86%. In most case-control studies (21/24 studies), positivity in cases was found to be higher than in controls, but odds ratios and confidence intervals were not reported.

CONCLUSION

The results are controversial. However, they arouse a great interest in the potential participation of HPV in breast carcinogenesis, but rather as an essential cause-effect participant, at least as a co-participant in some cases. The circumstance of HPV positivity in breast cancer can be criticized, but the elements that clearly demonstrate it in a number of cases are also relevant.

Prevalence of Human Papillomavirus Infection in Breast Cancer Cells from Thai Women

Breast cancer is the leading female cancer worldwide and is the most frequently diagnosed in Thai women. Its potential etiologic has not been clearly identified. Several recent reports could detect human papillomavirus (HPV) infection in breast cancer or benign breast lesions. HPV infection considered suggests being one of many risk factors for cancer development. The aim of this study was to determine the frequency of HPV infection in both breast cancer and benign breast lesion/tumor tissues. Seven hundred samples from Thai women were collected during 2013-2015 and statistically correlation between HPV infection, sociodemographic and histopathological parameters were also analyzed. HPV DNA detection and genotyping were performed by polymerase chain reaction and enzyme immunoassay, respectively. The results demonstrated that mean age of the patients were 41.76±12.53 years and 52.73±11.68 years for benign breast lesions/tumor and breast cancer samples, respectively. HPV DNA was detected in 25/700 (3.57%) samples, in which 10/350 (2.857%) from benign breast lesion/tumor samples and 15/350 (4.285%) from breast cancer samples. HPV 16 is the predominant types of this study, follow by HPV 33, 18, 35, 52. Most of HPV type detection samples belong to the high risk types, except 1/25 sample could be detected low risk type; HPV 6 which was presented as co-infection with the other high risk type. From sociodemographic and histopathological correlation analysis, all of studied parameters such as breast cancer history, hormone receptors status etc. did not show statistically significant correlated with HPV infection (P>0.05). In conclusion, the low frequency detection in this study suggests that HPV did not play the main important role for breast cancer development and represented highly controversial, but it may be causative agents of only a relative small proportion of all breast cancer or non-malignant breast lesion and it is the interesting data for further study in virus-associated cancer.

Presence of human papillomavirus DNA in breast cancer: a Spanish case-control study

BACKGROUND

Breast cancer is one of the most important neoplasia among women. It was recently suggested that biological agents could be the etiological cause, particularly Human Papilloma Virus (HPV). The aim of this study was to explore the presence of HPV DNA in a case-control study.

METHODS

We performed our study including 251 cases (breast cancer) and 186 controls (benign breast tumors), using three different molecular techniques with PCR (GP5/GP6, CLART® and DIRECT FLOW CHIP®).

RESULTS

HPV DNA was evidenced in 51.8% of the cases and in 26.3% of the controls (p < 0.001). HPV-16 was the most prevalent serotype. The odds ratio (OR) of HPV within a multivariate model, taking into account age and breastfeeding, was 4.034.

CONCLUSIONS

Our study, with methodological rigour and a sample size not previously found in the literature, demonstrate a significant presence of HPV DNA in breast cancer samples. A possible causal relationship, or mediation or not as a cofactor, remains to be established by future studies.

Low prevalence of human mammary tumor virus (HMTV) in breast cancer patients from Myanmar

BACKGROUND

Human mammary tumor virus (HMTV) is 90-95% homologous to mouse mammary tumor virus (MMTV), one of the causal agents of murine mammary tumors. HMTV (MMTV-like) sequences were reported to be present in human breast cancers from several populations with a prevalence range of 0-78%; however, the prevalence of HMTV in breast cancers from Myanmar remains unknown.

METHODS

Fifty-eight breast cancer samples from Myanmar women were examined in this study. DNA was isolated from formalin-fixed paraffin-embedded specimens, and HMTV envelope sequences were detected by semi-nested PCR. The sequence of the PCR products was also confirmed.

RESULTS

Only 1.7% (1 of 58) of the breast cancers were positive for HMTV, and the sequence of PCR products was 98.9% identical to the reference HMTV sequence (GenBank accession No. AF243039). The tumor with HMTV was grade III invasive ductal carcinoma, 7.0 cm in size with lymph node metastasis (T3, N1, M0).

CONCLUSIONS

We, for the first time, investigated the presence of HMTV in Myanmar breast cancer patients. In accordance with other Asian studies, the prevalence of HMTV in Myanmar was quite low, supporting the hypothesis that Asian breast cancers have different etiologies than in Western countries, where HMTV is more prevalent.

Association of human papillomavirus type 58 with breast cancer in Shaanxi province of China

A number of reports have identified HPV DNA in breast cancer specimens and HPV type 16, 18, 31, 33, 45, and 51 were more prevalent. HPV 58 was frequently detected in cervical cancer in Shaanxi China. The aim of the present study was to investigate whether HPV 58 present in breast cancer. 169 cases of breast cancer samples and 83 benign breast lesions were analyzed. Type specific primers and oligonucliotide probe were used for the detection of HPV 58 by conventional PCR and in situ hybridization techniques. The HPV 58 viral load were measured by qPCR. p16 protein expression were evaluated by immunohistochemistry. HPV 58 E7 DNA was detected in 25 out of 169 formalin fixed paraffin embedded breast cancer tissues (14.79%) by PCR, only 1 out of 83 non-malignant breast lesions showed positive (1.20%). The results of ISH showed that 17 out of 169 (10.06%) malignant samples were positive for HPV 58 E7, and only 1 out of 83 non-malignant lesions was positive. Positive p16 immunostaining was observed in all the HPV 58 E7 ISH positive cases, but 16 out of 98 cases with HPV negative were p16 positive. The presence of HPV 58 in both normal duct epithelial cells and carcinoma in situ along with its presence in the cancer cells of the same specimen indicated the possible causal role of HPV 58 in breast cancer. The findings provide a solid morphological evidence of the involvement of HPV 58 in breast cancer development.

Prevalence of papillomaviruses, polyomaviruses, and herpesviruses in triple-negative and inflammatory breast tumors from algeria compared with other types of breast cancer tumors

BACKGROUND

The possible role of viruses in breast cancer etiology remains an unresolved question. We hypothesized that if some viruses are involved, it may be in a subgroup of breast cancers only. Epidemiological arguments drove our interest in breast cancer subgroups that are more frequent in Africa, namely inflammatory breast cancer (IBC) and triple-negative breast cancer. We tested whether viral prevalence was significantly higher in these subgroups.

MATERIALS AND METHODS

One hundred fifty-five paraffin-embedded malignant breast tumors were randomly selected at the pathology laboratory of the University Hospital of Annaba (Algeria) to include one third of IBC and two thirds of non-IBC. They were tested for the presence of DNA from 61 viral agents (46 human papillomaviruses, 10 polyomaviruses, and 5 herpesviruses) using type-specific multiplex genotyping assays, which combine multiplex PCR and bead-based Luminex technology.

RESULTS

Viral DNA was found in 22 (17.9%) of 123 tumors. The most prevalent viruses were EBV1 and HPV16. IBC tumors carried significantly more viruses (any type) than non-IBC tumors (30% vs. 13%, p<0.04). Similarly, triple-negative tumors displayed higher virus-positivity than non-triple-negative tumors (44% vs. 14%, p<0.009).

CONCLUSIONS

Our results suggest an association between the presence of viral DNA and aggressive breast cancer phenotypes (IBC, triple-negative). While preliminary, they underline the importance of focusing on subgroups when studying viral etiology in breast cancer. Further studies on viruses in breast cancer should be conducted in much larger samples to confirm these initial findings.

Prevalence of human papilloma virus among women with breast cancer since 2005-2009 in Isfahan

Background:

Human papilloma virus (HPV) DNA has been detected in breast carcinoma by different laboratorial techniques, suggesting that the virus could play a role in the pathogenesis of this tumor.

Materials and Methods:

It was a descriptive study. Systematic random sampling was used for selecting 55 cases of breast cancer and 51 controls of benign breast lesions from the file of Seyedshohada hospital of Isfahan since 2005-2009. A total of 106 paraffin-embedded specimens were selected and HPV DNA was analyzed by polymerase chain reaction and sequenced for different types of HPV in case of positivity for HPV DNA. Data analysis was performed by SPSS 16 software using descriptive statistic, Chi-square, and Fisher's exact tests.

Results:

Out of 55 malignant and 51 benign breast specimens, 18.2% (10) and 13.7% (7) were positive to HPV DNA, respectively (P = 0.53); 70% (7) malignant and 43% (3) benign breast specimens were positive to high-risk HPV genotypes. In malignant specimens, the most common high- and low-risk genotypes were HPV-16 (3.6%) and HPV-11 (3.6%), respectively. In benign specimens, the most common high- and low-risk genotypes were HPV-31 (3.9%) and HPV-43 (3.9%), respectively. Among malignant and benign specimens, ductal carcinoma and fibro adenoma were the most common lesions positive to different types of HPV, respectively.

Conclusion:

This study demonstrated the presence of HPV genome in both malignant and benign tumor tissues in women with breast lesions in Isfahan; therefore, further larger epidemiologic studies need to be analyzed to establish the exact role of this virus in the pathogenesis of breast cancer.

Absence of human papillomavirus in patients with breast cancer in north-west China

The purpose of this study was to investigate the human papillomavirus (HPV) infection rate in malignant and benign breast tumours in north-west Chinese patients. Unselected fresh tissue samples were extracted from 48 invasive breast carcinoma and 30 benign breast tumours between August 2009 and August 2010. We used real-time fluorescence quantitative PCR (FQ-PCR) and in situ hybridization to detect HPV 6, 11 and 16, 18 sequences targeting the E6, E7 open-reading frame. The presence of HPV 6, 11 was only demonstrated in the 3 (10%) benign phyllodes tumour specimens. No HPV infection was detected in all the 48 invasive breast carcinoma. Specifically, all the positive specimens were detected by in situ hybridization but not in FQ-PCR. In addition, we found that the positive specimens became negative after 3 months frozen at -70°C. HPV was absent in patients with breast tumours in north-west China.

The role of human papillomavirus infection in breast cancer

Breast cancer is the leading female cancer and the third most common cause of cancer deaths worldwide. Many studies have suggested a possible link between breast cancer pathogenesis and viral infection, particularly mouse mammary tumour virus, simian virus 40, Epstein-Barr virus, and human papillomavirus (HPV). A significant number of recent studies have reported that approximately 29% of human breast cancer tissues were positive for high-risk HPV subtypes, especially HPV subtypes 16, 18, or 33. In contrast, several other investigations did not detect any HPV subtypes in either breast cancer tissue or normal breast tissue from patients diagnosed with breast cancer. Given these conflicting data and the established complexity of the association between HPV with other cancers, a definitive relationship between human breast cancer and HPV infection has not been determined. Recent advances in laboratory methodologies aim to overcome the inherent challenges in detecting HPV in breast cancer tissue. There is an urgent need to obtain additional evidence in order to assess the possibility of breast cancer prevention using HPV vaccines.

Treatment of Primary Biliary Cirrhosis: A new challenge?

Primary biliary cirrhosis (PBC) is characterized by unknown etiologies, anti-mitochondrial antibodies, injury of the biliary duct and the lack of a definite remedy. The etiologies of PBC have been well-discussed, including microorganisms and xenobiotics as the triggers for initiating the disease, and an abnormality of immune-tolerance. Recently, several animal models of PBC have been developed that may lead to the development of new therapies. Here, we reviewed the articles that address the etiology of PBC and the therapy for this disease for the confirmation of our current positions and future directions.