Breast cancer is the second leading cause of death due to cancer in women worldwide. Breast cancer research has gained worldwide attention and novel approaches have been proposed to combat the disease. This has largely been made possible by generous funding support for breast cancer research and awareness from numerous national and international organizations which has led to improved breast cancer screening, diagnosis and advances in treatment. The exact factors that lead to breast cancer remain unclear. It is estimated that 5–10% of breast cancers are linked to family history and inherited gene mutations. Several inherited mutated genes that may increase the risk for breast cancer have been identified. The most common are breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). These two gene mutations can significantly increase the risk of both breast and ovarian cancer. While various risk factors have been associated with breast cancer, recent studies suggest that the human microbiome may be linked to breast carcinogenesis through the modification of systemic estrogen levels.


A number of studies have shown that the human microbiome can have a tremendous impact on physiology, both in health and disease. The microbiome is already associated with diseases such as diabetes, obesity, cancer, diarrhea, autoimmune and mental disorders. Amieva, M. et al (2016) described the role of Helicobacter pylori bacteria in gastric cancer and Arthur, J.C. et al. (2013) described the interplay between inflammation, microbiota and colorectal cancer (1, 2). Breast milk and tissue has also been shown to contain unique and diverse microbiota, partially derived from the translocation of gut microorganisms (3–5).


Due to technological advances, bacteria from a microbial population can be identified by sequencing of the 16S rRNA gene and then compared to known bacterial sequence databases. In a recent study by Wang H. et al. (2017), 16S rRNA gene sequencing was used to show that the microbiome profile of cancerous breast tissue is distinct (and more pronounced in more aggressive disease) from that of benign breast tissue (6). In this study, breast tissue samples were collected from 57 individuals with breast cancer and 21 healthy females. A decrease in abundance of Methylobacterium in the individuals with cancer compared to healthy controls was identified. When urine samples from both groups were compared, the biggest microbiome differences were found to be due to menopausal status, and the urinary microbiome of the individuals with cancer showed increased gram-positive bacteria associated with skin flora.


In microbiome research, there are common challenges when dealing with rare and precious microbiome samples. The challenges can range from limited amounts of DNA/RNA, to the presence of inhibitors in microbiome samples, which can interfere with nucleic acid isolation and sensitivity of downstream applications such as next-generation sequencing. To overcome these challenges, in the study by Wang, H. et al. (2017), the MO BIO PowerMag Microbiome RNA/DNA Isolation Kit was chosen (now QIAGEN’s MagAttract PowerMicrobiome DNA/RNA Kit), and was used to extract total DNA from breast tissue, environmental controls, urine and oral rinse pellets. Read the publication.


Find out more why QIAGEN microbiome kits with Inhibitor Removal Technology are the preferred choice among researchers.


This new study is just one of many fascinating examples of the application of QIAGEN microbiome solutions to understand how the human microbiome influences human health and disease. It’s an exciting time – we will potentially see many disease secrets revealed, placing researchers in a strong position to find new ways to combat them.




  1. Amieva, M. and Peek, R.M. Jr. (2016) Pathobiology of Helicobacter pylori-Induced Gastric Cancer. Gastroenterology 150, 64–78.
  2. Arthur, J.C. and Jobin, C. (2013) The complex interplay between inflammation, the microbiota and colorectal cancer. Gut Microbes 4, 253–8.
  3. Urbaniak, C. et al. (2014) Microbiota of human breast tissue. Appl. Environ. Microbiol. 80, 3007–14.
  4. Xuan, C. et al. (2014) Microbial dysbiosis is associated with human breast cancer. PLoS One. 9, e83744.
  5. Donnet-Hughes, A. et al. (2010) Potential role of the intestinal microbiota of the mother in neonatal immune education. Proc. Nutr. Soc. 69, 407–415.
  6. Wang, H. et al. (2017) Breast tissue, oral and urinary microbiomes in breast cancer. Oncotarget 8, 88122–88138.