Catching viral breast cancer

We have considered viruses and their contribution to breast cancer. Mouse mammary tumour virus The prevalence of mouse mammary tumour virus (MMTV) is 15-fold higher in human breast cancer than in normal and benign human breast tissue controls. Saliva is the most plausible means of transmission. MMTV has been identified in dogs, cats, monkeys, mice and rats. The causal mechanisms include insertional oncogenesis and mutations in the protective enzyme ABOBEC3B. Human papilloma virus The prevalence of high risk human papilloma viruses (HPV) is frequently six fold higher in breast cancer than in normal and benign breast tissue controls. Women who develop HPV associated cervical cancer are at higher than normal risk of developing HPV associated breast cancer. Koilocytes have been identified in breast cancers which is an indication of HPV oncogenicity. The causal mechanisms of HPVs in breast cancer appear to differ from cervical cancer. Sexual activity is the most common form of HPV transmission. HPVs are probably transmitted from the cervix to the breast by circulating extra cellular vesicles. Epstein Barr virus The prevalence of Epstein Barr virus (EBV) is five fold higher in breast cancer than in normal and benign breast tissue controls. EBV is mostly transmitted from person to person via saliva. EBV infection predisposes breast epithelial cells to malignant transformation through activation of HER2/HER3 signalling cascades. EBV EBNA genes contribute to tumour growth and metastasis and have the ability to affect the mesenchymal transition of cells. Bovine leukemia virus Bovine leukemia virus (BLV) infects beef and dairy cattle and leads to various cancers. The prevalence of BLV is double in human breast cancers compared to controls. Breast cancer is more prevalent in red meat eating and cow’s milk consuming populations. BLV may be transmitted to humans from cattle by the consumption of red meat and cow’s milk. Conclusion The evidence that MMTV, high risk HPVs and EBVs have causal roles in human breast cancer is compelling. The evidence with respect to BLV is more limited but it is likely to also have a causal role in human breast cancer.

Absence of Human Papillomavirus in Benign and Malignant Breast Tissue

Background & Objective: Malignant breast tumors, which are one of the most important deadly cancers in women, like many other cancers, are proposed to be related to viruses etiologically. Proper management of breast carcinoma necessitates an identification of the etiological factors. Human Papillomavirus is considered to have an etiological role in breast carcinoma. We carried out this study to find out if Human Papillomavirus-DNA is present in the malignant and benign breast tissue in our patients. Methods: Seventy five paraffin-embedded breast cancer tissues and 75 normal breast tissues and benign breast lesions were examined in this study (case-control) to look for Human Papillomavirus-DNA employing Nested Polymerase Chain reaction. The tissues were examined over a period of ten years in the pathology department of the Pathobiology Laboratory Center of Tehran. Results: No Human Papillomavirus-DNA was found in any of the malignant or control group specimens. Conclusion: Our results showed no evidence of Human Papillomavirus in cancerous and benign tissues, which is consistent with some other studies in English medical literature. More investigations using more specimens from different parts of the country are required to confirm the presence or absence of any connection between Human Papillomavirus and development of breast carcinoma in Iran.

Percutaneous Needle Biopsies of the Breast in Women Younger than 35 Years: Minimally or Excessively Invasive?

Percutaneous needle biopsy (PNB) of the breast is commonly used for diagnosis of breast pathology, but has been less studied in young women. We sought to determine the effectiveness and necessity of PNB in patients younger than 35 years of age. The charts of sequential patients <35 years who underwent PNB between February 2013 and May 2016 were reviewed; 181 PNB were performed in 127 patients. Median age was 30 years (13–34). Indications for PNB were Breast Imaging Reporting and Data System (BIRADS) ≥4 in 137 (75.7%) cases, with mass on imaging in 139 (76.8%). Carcinoma was diagnosed in 12 (6.6%), PNB in eight unique patients (6.3%). Other PNB pathology included atypia in four (2.2%) patients; papillary lesion, five (2.8%); benign lymph node, 10 (5.5%); fibroepithelial lesion, 15 (8.3%); benign breast tissue, 63 (34.8%); and fibroadenoma, 72 (39.8%). Women with atypia or malignancy were older than those with benign findings (30.9 vs 28.0 years, P = 0.002). No other patient or imaging factors were significantly associated with pathologic diagnosis on PNB. Routine PNB for all BIRADS 4 findings may be over-used in young women as most results are benign and subsequent surgical findings are concordant. Improved diagnostic accuracy of breast imaging is warranted to reduce unnecessary procedures.