Human Mammary Tumor Virus (HMTV) Infection and Risk of Human Breast Cancer: An Adaptive Meta-Analysis for Case-Control Studies
Objective: There is ongoing debate about the association between Human Mammary Tumor Virus (HMTV) infection and breast cancer. A systematic review (SR) published in 2014 revealed that there was a statistically significant association. However, there was suspected duplication of the studies selected in that SR, and it also presented the need for a more detailed subgroup analysis by region. Therefore, the present study repeated the meta-analysiswith the addition of relevant papers published before October 2015. Methods: Using the papers selected for the previous SR, a list was made of the references, and the “cited articles” and “similar articles” provided by PubMed. Of these, we only selected case-control studies that used PCR to detect the HMTV gene in tissue. The criterion for duplication was papers that showed identical researcher names or affiliated institutions. Among duplicated papers, the one with the largest number of samples was chosen. The meta-analysis was used to obtain summary odds ratio (SOR) and 95% confidence interval (CI). Results: A total of 13 case-control studies were selected. The total number of the case and control groups was 1,878 and 1,204 persons, respectively. The results of the meta-analysis for these 13 papers showed that HMTV infection increased the risk of breast cancer (SOR=8.37, 95% CI: 2.29-23.39; I-squared = 98.4%). Conclusion: In the sub-group analysis, there was statistical significance for North America, the Mediterranean, and Australia. The results of this study support the claim that HMTV infection increases the risk of human breast cancer.
Jong-Myon Bae, Eun Hee Kim