Evaluation Frequency of Merkel Cell Polyoma, Epstein-Barr and Mouse Mammary Tumor Viruses in Patients with Breast Cancer in Kerman, Southeast of Iran.

Breast cancer is the most common cancer among women worldwide. Roles of the Epstein-Barr, Merkel cell polyoma and mouse mammary tumor viruses in breast carcinogenesis are still controversial although any relationship would clearly be important for breast cancer etiology, early detection and prevention. In the present study associations between EBV, MMTV and Merkel cell polyoma virus and breast cancer in 100 Iranian patients were evaluated using paraffin-embedded tissues. EBER RNA and expression of p53 and large T antigen were evaluated by real time PCR and CD34, p63, HER2, PR and ER markers were studied by immunohistochemistry. EBV was detected in 8/100 (8%), MMTV in 12/100 (12%), MPy in 3/100 (3%) and EBER RNA in 18/100 (18%) cases. None of the control samples demonstrated any of the viruses. p53 was suppressed in EBV, MPy and MMTV positive samples. The large T antigen rate was raised in MPy positive samples. Our results showed that EBV, MMTV and the Merkel cell polyoma virus are foundwith some proportion of breast cancers in our patients, suggesting that these viruses might have a significant role in breast cancer in Kerman, southeast of Iran.

Human endogenous retrovirus type K antibodies and mRNA as serum biomarkers of early-stage breast cancer.

A simple and accurate test to detect early-stage breast cancer has not been developed. Previous studies indicate that the level of human endogenous retrovirus type K (group HERV-K(HML-2)) transcription may be increased in human breast tumors. We hypothesized that HERV-K(HML-2) reactivation can serve as a biomarker for early detection of breast cancer. Serum samples were collected from women without cancer (controls) and patients with ductal carcinoma in situ (DCIS) and invasive breast cancer. ELISA assays were used to detect serum anti-HERV-K(HML-2) antibody titers. RNA was extracted from sera and analyzed by real-time RT-PCR to quantitate the level of HERV-K(HML-2) mRNA. We measured significantly higher serum mRNA and serum antibody titers against HERV-K(HML-2) proteins in women with DCIS and stage I disease than in women without cancer. At optimized cutoffs for the antibody titers, the assay produced an area under the receiver operating characteristic curve (AUC) of 0.89 (95% confidence interval 0.77-1.00) for DCIS and of 0.95 (95% confidence interval 0.89-1.00) for invasive breast cancer. These AUCs are comparable to those observed for mammograms. We also found that serum HERV-K(HML-2) mRNA tended to be higher in breast cancer patients with a primary tumor who later on developed the metastatic disease than in patients who did not develop cancer metastasis. Our results show that HERV-K(HML-2) antibodies and mRNA are already elevated in the blood at an early stage of breast cancer, and further increase in patients who are at risk of developing a metastatic disease.

Epstein-Barr virus, human papillomavirus and mouse mammary tumour virus as multiple viruses in breast cancer.

BACKGROUND: The purpose of this investigation is to determine if Epstein Barr virus (EBV), high risk human papillomavirus (HPV), and mouse mammary tumour viruses (MMTV) co-exist in some breast cancers. MATERIALS AND METHODS: All the specimens were from women residing in Australia. For investigations based on standard PCR, we used fresh frozen DNA extracts from 50 unselected invasive breast cancers. For normal breast specimens, we used DNA extracts from epithelial cells from milk donated by 40 lactating women. For investigations based on in situ PCR we used 27 unselected archival formalin fixed breast cancer specimens and 18 unselected archival formalin fixed normal breast specimens from women who had breast reduction surgery. Thirteen of these fixed breast cancer specimens were ductal carcinoma in situ (dcis) and 14 were predominantly invasive ductal carcinomas (idc). RESULTS: EBV sequences were identified in 68%, high risk HPV sequences in 50%, and MMTV sequences in 78% of DNA extracted from 50 invasive breast cancer specimens. These same viruses were identified in selected normal and breast cancer specimens by in situ PCR. Sequences from more than one viral type were identified in 72% of the same breast cancer specimens. Normal controls showed these viruses were also present in epithelial cells in human milk - EBV (35%), HPV, 20%) and MMTV (32%) of 40 milk samples from normal lactating women, with multiple viruses being identified in 13% of the same milk samples. CONCLUSIONS: We conclude that (i) EBV, HPV and MMTV gene sequences are present and co-exist in many human breast cancers, (ii) the presence of these viruses in breast cancer is associated with young age of diagnosis and possibly an increased grade of breast cancer.

Epstein-Barr virus is seldom found in mammary epithelium of breast cancer tissue using in situ molecular methods.

Epstein-Barr virus (EBV) has been proposed as a possible etiological agent of breast cancer based on 21 reports of EBV in malignant breast tissues. Most of these studies used standard and nested solution polymerase chain reaction (PCR) techniques, both disadvantaged by susceptibility to contamination from laboratory EBV, and the inability to localize the signal to a specific cell type. To avoid these issues, we used in situ molecular methods of viral detection to reassess the frequency of EBV in malignant breast tissue. We used a commercial in situ hybridization (ISH) system with an EBER genome target, and a non-commercial in situ PCR (IS-PCR) method using primers specific for the BamH1 region. The assays were performed on malignant breast tissue sections from 70 breast cancer patients at the M. D. Anderson Cancer Center, Houston, TX. EBV was found in mammary epithelial cells, the cell type from which most breast cancers arise, in 2/70 (2.9%) of specimens using IS-PCR and in none of the specimens using ISH. Based on these findings that EBV was present in human mammary epithelial cells so infrequently, it is unlikely to play a causative role in most types of breast cancer.

A mouse mammary tumor virus env-like exogenous sequence is strictly related to progression of human sporadic breast carcinoma.

A viral etiology of human breast cancer (HBC) has been postulated for decades since the identification of mouse mammary tumor virus (MMTV). The detection of MMTV env-like exogenous sequences (MMTVels) in 30% to 40% of invasive HBCs increased attention to this hypothesis. Looking for MMTVels during cancer progression may contribute to a better understanding of their role in HBC. Herein, we analyzed HBC preinvasive lesions for the presence of MMTVels. Samples were obtained by laser microdissection of FFPE tissues: 20 usual-type ductal hyperplasias, 22 atypical ductal hyperplasias (ADHs), 49 ductal carcinomas in situ (DCISs), 20 infiltrating ductal carcinomas (IDCs), and 26 normal epithelial cells collateral to a DCIS or an IDC. Controls included reductive mammoplastic tissue, thyroid and colon carcinoma, and blood samples from healthy donors. MMTVels were detected by fluorescence-nested PCR. DNA samples from the tissues of nine patients were analyzed by real-time quantitative PCR, revealing a different viral load correlated with stage of progression. Furthermore, as never previously described, the presence of MMTVels was investigated by chromogenic in situ hybridization. MMTVels were found in 19% of normal epithelial cells collateral to a DCIS or an IDC, 27% of ADHs, 82% of DCISs, and 35% of IDCs. No MMTVels were found in the control samples. Quantitative PCR and chromogenic in situ hybridization confirmed these results. These data could contribute to our understanding of the role of MMTVels in HBC.

No evidence for an association of human papillomavirus and breast carcinoma.

Breast cancer represents a serious public health problem worldwide, for its high incidence, morbidity, mortality, and its high cost treatment. It is known that breast cancer is a multifactorial disease, possessing various risk factors, among which include hormonal factors, genetic and environmental. The role of viruses in breast carcinogenesis is controversial. This study aims to evaluate the expression of HPV 6, 11, 16, and 18 by polymerase chain reaction (PCR) in invasive ductal breast carcinoma. We analyzed 90 women diagnosed with invasive ductal breast carcinoma, of which the extracted DNA was amplified, quantified and tested for DNA subtypes 6, 11, 16, and 18 by PCR. The research carried out in 79 samples of HPV DNA, proved negative. Our study demonstrates no association between the most prevalent types of HPV and breast cancer.

No association of mouse mammary tumor virus-related retrovirus with Japanese cases of breast cancer.

Mouse mammary tumor virus (MMTV) is the causative agent of breast tumors in mice. Recently, DNA sequences homologous or closely related to MMTV env gene have been specifically detected in breast cancer tissue from significant numbers of American, Australian, and Tunisian women, suggesting a viral etiology for at least a part of human breast cancer. However, the viral sequences have not been detected from any of breast cancer samples in several subsequent studies. Thus, whether MMTV-related retrovirus is a causative agent of human breast cancer remains controversial. To demonstrate if MMTV-related retrovirus is involved in Japanese cases of breast cancer, breast tissue specimens from 46 breast cancer patients and 3 patients with benign mammary tumors were investigated. Extensive analysis using PCR and Southern blot hybridization, however, could not detect the MMTV env gene-like sequence in any of the samples tested as well as in MCF7 cells that has previously been described as a positive control. Thus, MMTV itself or MMTV-related retrovirus is not associated with breast carcinogenesis in Japanese women, and it is unclear whether this conclusion is merely a reflection of regional differences in its epidemics.

Detection of human papillomavirus DNA by DNA chip in breast carcinomas of Korean women.

It remains unclear whether there is an association between human papillomavirus (HPV) infection and human breast cancer. The aim of this study was to investigate the presence of HPV DNA in breast carcinomas of Korean women and to examine the possible association between HPV and breast cancer development. For this purpose, HPV DNAs from 154 patients, including 123 patients with breast carcinoma and 31 with intraductal papilloma, and nipple tissue from 27 cancer patients were examined using the DNA chip method. HPV DNA was detected in 8 breast carcinomas (6.5%) but in no intraductal papilloma. All detected HPV genotypes were of high-risk groups. There was a slightly increased incidence in papillary carcinomas (11.5%) and invasive ductal carcinomas with adjacent intraductal papillomas (11.8%) compared to the other histological subtypes (3.2-4.3%), although the difference was not statistically significant (p = 0.126). The presence of HPV DNA was not correlated with specific prognostic predictors of disease. High-risk HPV DNA sequences were present in 6.5% of Korean patients with breast tumors. However, this study could not demonstrate whether or not such HPVs directly contribute to the development of breast cancer.

Analysis of Epstein-Barr virus reservoirs in paired blood and breast cancer primary biopsy specimens by real time PCR.

INTRODUCTION: Epstein-Barr virus (EBV) is present in over 90% of the world's population. This infection is considered benign, even though in limited cases EBV is associated with infectious and neoplastic conditions. Over the past decade, the EBV association with breast cancer has been constantly debated. Adding to this clinical and biological uncertainty, different techniques gave contradictory results for the presence of EBV in breast carcinoma specimens. In this study, minor groove binding (MGB)-TaqMan real time PCR was used to detect the presence of EBV DNA in both peripheral blood and tumor samples of selected patients. METHODS: Peripheral blood and breast carcinoma specimens from 24 patients were collected. DNA was extracted and then amplified by MGB-TaqMan real time PCR. RESULTS: Of 24 breast tumor specimens, 11 (46%) were positive for EBV DNA. Of these 11 breast tumor specimens, 7 (64%) were also positive for EBV DNA in the peripheral blood, while 4 (36%) were positive for EBV DNA in the tumor, but negative in the blood. CONCLUSION: EBV was found at extremely low levels, with a mean of 0.00004 EBV genomes per cell (range 0.00014 to 0.00001 EBV genomes per cell). Furthermore, our finding of the presence of EBV in the tumor specimens coupled to the absence of detection of EBV genomic DNA in the peripheral blood is consistent with the epithelial nature of the virus. Because of the low levels of viral DNA in tumor tissue, further studies are needed to assess the biological input of EBV in breast cancer.

Presence of mouse mammary tumour-like virus gene sequences may be associated with morphology of specific human breast cancer.

BACKGROUND: Mouse mammary tumour virus (MMTV) has a proven role in breast carcinogenesis in wild mice and genetically susceptible in-bred mice. MMTV-like env gene sequences, which indicate the presence of a replication-competent MMTV-like virus, have been identified in some human breast cancers, but rarely in normal breast tissues. However, no evidence for a causal role of an MMTV-like virus in human breast cancer has emerged, although there are precedents for associations between specific histological characteristics of human cancers and the presence of oncogenic viruses. AIM: To investigate the possibility of an association between breast cancer and MMTV-like viruses. METHODS: Histological characteristics of invasive ductal human breast cancer specimens were compared with archival MMTV-associated mammary tumours from C3H experimental mice. The presence of MMTV-like env DNA sequences in the human breast cancer specimens was determined by polymerase chain reaction and confirmed by Southern hybridisation. RESULTS: MMTV-like env gene sequences were identified in 22 of 59 (37.3%) human breast cancer specimens. Seventeen of 43 (39.5%) invasive ductal carcinoma breast cancer specimens and 4 of 16 (25%) ductal carcinoma in situ specimens had some histological characteristics, which were similar to MMTV-associated mouse mammary tumours. However, these similarities were not associated with the presence or absence of MMTV-like gene sequences in the human breast tumour specimens. A significant (p = 0.05) correlation was found between the grade of the human breast cancer and similarity to the mouse mammary tumours. The lower the grade, the greater the similarity. CONCLUSION: Some human breast cancer specimens, in which MMTV-like env DNA sequences have been identified, were shown to have histological characteristics (morphology) similar to MMTV-associated mouse mammary tumours. These observations are compatible with, but not conclusive of, an association between the presence of MMTV-like env DNA sequences and some human breast cancers.

Elevated expression of the tumor suppressing protein p53 is associated with the presence of mouse mammary tumor-like env gene sequences (MMTV-like) in human breast cancer.

Mouse mammary tumor virus (MMTV) has a proven role in breast carcinogenesis in wild mice and genetically susceptible laboratory inbred mice. The carcinogenic characteristics of this virus are enhanced by estrogen and other steroid hormones. MMTV-like envelope gene sequences, with 95% homology to MMTV have been identified in approximately 40% of breast cancers in US, Australian and Argentinian women. The presence of such sequences indicates the presence of a replication competent MMTV-like virus in human breast tumors. Whether an MMTV-like virus contributes to human breast cancer remains to be demonstrated. Non-statistically significant differences in p53 expression between MMTV-like positive and negative human breast cancers have previously been observed. As high p53 protein expression is associated with aggressive breast carcinogenesis we sought to determine if there were associations between the presence of MMTV-like gene sequences and elevated p53 expression in both invasive ductal carcinomas (IDC) and ductal carcinomas in situ (DCIS). We also investigated the expression of other biomarkers which are commonly associated with human breast cancer. These included estrogen receptor, progesterone receptor, Ki67, Cyclin D1, Bcl-2 and HER-2. Using polymerase chain reaction (PCR) analyses, MMTV-like envelope gene sequences were detected in 15 (75%) of 20 IDC specimens and 5 (23%) of 22 DCIS specimens. The average percentage of p53 positive cells in MMTV-like positive IDC specimens was 69% as compared to 44% in MMTV-like negative specimens (p for difference = 0.067). The average percentage of p53 positive cells in MMTV-like positive DCIS specimens was 93% as compared to 35% in MMTV-like negative specimens (numbers too few for statistical analysis). There was an increased intensity of p53 expression in IDC and DCIS specimens that were MMTV-like positive compared to those that were MMTV-like negative. There were no statistically significant differences in age, grade, and percentage of average positive cells for ERa, PR, Ki67, cyclin D1, Bcl-2, and HER-2, between MMTV-like positive and negative breast cancer specimens. Although these observations do not provide evidence of causality, they are consistent with a role for MMTV-like viruses in some human breast cancers.