Data Availability StatementAll data used and analyzed are available from your corresponding author. heterogeneity and the multivariable-adjusted OR and related 95% CI were applied by meta-analysis and forest storyline across studies. All statistical analyses were performed using Stata 14.1. Result Based on a comprehensive literature search, 9 case-control studies were included for meta-analysis. The combination of all included studies showed that BLV illness is associated with an increased risk of breast cancer [summary OR (95% CI) 2.57 (1.45, 4.56)]. Summary This is the 1st meta-analysis to analyze a potential association between BLV illness and the risk of breast tumor. Control of the infection in cattle herds and screening of the milk and dairy products may help to reduce the transmission of the disease to humans. family. The disease is definitely further classified in Orthoretrovirinae subfamily, and deltaretrovirus genus which is considered as a possible zoonotic illness . The main hosts for BLV is definitely cattle but it can infect additional animal species such as water buffalo, sheep, alpaca, rabbits, rats, pigs, and goats, as well. The prevalence of BLV illness is high in cattle herds and varies from about 39 to 100% in beef and dairy herds, respectively. Although BLV can easily transmit through infected blood and milk, it causes disease in less than 5% of infected cattle [8, 9]. BLV is definitely associated with chronic lymphatic leukemia and the illness of mammary cells might be associated with breast tumor in the hosts. The BLV tax protein offers some regulatory functions (transcription activator) and could be associated with transformation through inhibition of DNA restoration system and disruption of tumor suppressor genes . The mechanism of BLV transmission to humans is not known, however, uncooked milk usage can transmit the disease from cattle to human population . The study by Buehring et al. CGP 65015 showed the genome and antibodies against the capsid protein (P24) of BLV can be found in woman blood samples [8, 9]. Buehring et al. recognized the BLV DNA in the breast cells of 80% of ladies with breast cancer in compare with 41% of bad control group . Because there are some discrepancies regarding the association between BLV and breast tumor, the association of this disease like a risk element for breast cancer development remains controversial. The present study aimed to find out any possible association between BLV and breast cancer through conducting a systematic evaluate and meta-analysis. Method Search strategy This study was done based on the PRISMA (Desired Reporting Items for Systematic Evaluations and Meta-Analyses) CGP 65015 recommendations. Systematic literature search was carried out by self-employed reviewers and all related content articles from global databases were collected from January 1995 to January 2020 . All case-control studies that investigated the BLV illness in breast cancers were collected from well-known databases such as the PubMed, Google Scholar, Web of Technology, Scopus, and EMBASE. The Mesh-indexed keywords, including breast cancer, Bovine Leukemia disease OR BLV and their synonyms were used. Additional related content articles were assessed by critiquing the references of the selected publications and evaluations as well as the excluded ones. Study selection All the content articles were imported into Endnotes software version X7and the duplicates were removed. Then, the title and abstract of the content articles were analyzed to exclude all irrelevant publications. Full-texts of the remaining content articles were examined and disagreements between the reviewers were resolved. All remaining content articles were S1PR2 included. All those responsible for searching and filtering the content articles were contacted by email along with other Virtual Contact Methods. Eligibility criteria The following criteria were applied for the selection of qualified studies in this study: All BLV case-control and prevalence studies published in English language, publication day between 1995 to January 2020, availability of the full-text, and software of standard assays for the detection of BLV nucleic acid and antigens, including RT-PCR, Immunohistochemistry (IHC), In situ hybridization (ISH), ELISA (enzyme-linked immunosorbent assay) Nested PCR and In situ PCR assays. The exclusion criteria were as follows: Studies published in languages other than English, studies concerning breast tumor association with additional viruses rather than BLV, studies analyzing the prevalence of BLV illness in male individuals, article forms of systematic review, meta-analysis, case statement, letter to the editor, and conference abstracts. Data extraction Data extraction for the selected studies carried out by two self-employed reviewers. The extracted data included: the authors name, yr of publication, country, geographical area, type of study, sample type, target gene, the sample CGP 65015 size, number of BLV positive samples, mean age, and detection method. Quality assessment After selection of the relevant studies in terms of the title and material, the Newcastle- Ottawa assessment scale (NOS) was used to evaluate the quality of the content CGP 65015 articles. The NOS is used to evaluate three CGP 65015 quality guidelines of selection, Comparability, and Exposure..