Introduction Hannah Wang, Jessica Altemus, Farshad Niazi, Holly Green, Benjamin C. Calhoun, Charles Sturgis, Stephen R. Grobmyer and Charis Eng. “Breast tissue, oral and urinary microbiomes in breast cancer”. Oncotarget. Published on August 14, 2017.
The title for chosen article is “Breast tissue, oral and urinary microbiomes in breast cancer”, written by Wang, Altemus, Niazi, Green, Calhoun, Sturgis, Grobmyer & Eng (2017). The article discusses on the differences in the bacterial composition of breast tissue of healthy women vs. women with breast cancer. The research team has discovered for the first time that healthy breast tissue contains more of the bacterial species Methylobacterium, a finding which could offer a new perspective in the battle against breast cancer.
Breast cancer is the most common malignant tumor and second only to lung and bronchus cancer as the cause of cancer-related deaths in women, because it often leads to metastatic disease (Siegel, Miller & Jemal, 2016). Bacteria that have the potential to abet breast cancer are present in the breasts of cancer patients, while beneficial bacteria are more abundant in healthy breasts, where they may actually be protecting women from cancer, according to Gregor Reid, PhD, and his collaborators. Support for environmental factors comes from migration studies showing an increased incidence of breast cancer among migrants and their descendants after they move from a region of low breast cancer risk to a region of high risk (Shimizu et al., 1991; Le et al., 2002). A breast tissue microbiome exists in a cohort of Canadian and Irish women (Urbaniak et al., 2014). The bacterial profiles differ in breast tissue of healthy subjects and normal adjacent tissue of breast cancer patients, some of the bacteria that were relatively more abundant in breast cancer patients had the ability to induce DNA double-stranded breaks (Urbaniak et al., 2016). Thus, indicate that there are prove that breast cancer tissue associated with the increase level of bacteria compared to healthy breast tissue.
Breast cancer is a disease that normally found in women and there are many contributing factors that lead to breast cancer. In this article, they found that microbiome is not only living on gut but also found in human breast that influence many diseases. Most research has been done on the gut microbiome, or bacteria in the digestive tract. Researchers have long suspected that a microbiome exists within breast tissue and plays a role in breast cancer but it has not yet been characterized. So, the research team has taken the first step toward understanding the composition of the bacteria in breast cancer by examine the microbial differences in healthy and cancerous breast tissue.
Article summary As indicated in the article, the authors investigate if the breast cancer tissue is associated with a microbiomic profile distinct from that benign breast tissue. They also test if the microbiomes of more distant sites such as oral cavity and urinary tract lead to the dysbiosis as well. Dysbiosis also known as the condition of having imbalances in the microbial communities either in or on the body that associated with many diseases.
To test the hypothesis, the sample of oral and urine taken from the patient having cancerous breast tissue and non-cancer tissue being examined. After comparing the microbiomes for different sites in the patients, they found that there is significant abundance of Methylobacterium in non-cancer tissue compared to the Methylobacterium in cancerous tissue.
Then the authors conduct another test to examine if the microbiomes located in the oral cavity associated to dysbiosis for breast cancer. The results show that there are no significant differences in oral sample taken from cancerous breast tissue and non-cancer. So the result indicates that the microbiomes in that oral cavity does not relate to the microbiomes in that cancerous breast tissue.
Next, they examine the microbiomes in urine with those in the cancerous tissue. Urine sample analysis showed that microbiomic differences is influenced by menopausal status, in which there are significant increase of gram-positive bacteria of independent menopausal status in cancer patients. The increased gram-positive bacteria are Corynebacterium, Staphylococcus, Actinomyces and Propionibacteriaceae. While there are decreased level of Lactobacillus in postmenopausal patients.
Critical evaluation The article provides a new insight to further study the relation of microbiomes associate dysbiosis in breast cancer. Moreover, this article is the first study to examine both breast tissue and distant sites of the body for bacterial differences in breast cancer. They also hope to find a biomarker that would help medical field diagnoses breast cancer quickly and easily. Thus, hope to use microbiomics right before breast cancer forms and then prevent cancer with probiotics or antibiotics.
The methods used to investigate the correlation are not well explained and hard to understand with the changing terms used in the articles even for the same points. The information is not well organized with unclear explanation for each figure. Besides, the figures compiled in this article are really hard to be interpreted especially for the readers that have no scientific background study. Figures used in this article do not helpful for the reader to get a full picture of the whole study. But, it can’t be denied that overall arrangement for the article is arranged in detailed. The part of introduction is being well explained that increases readers understanding. The additional explanations of the terms used in the experiments as stated at the end of the article also allow the readers to understand how the methods being implemented.
Additionally, it would be helpful if the aim and test conducted in this article is explained in a simple form, text and figures. Without a clear picture of picture of the correlation, it is difficult to understand the experiment.
References Cleveland Clinic. (2017, October 6). Breast cancer linked to bacterial imbalances: Study compares bacterial composition in healthy vs. cancerous breast tissue. ScienceDaily. Retrieved October 11, 2017 from www.sciencedaily.com/releases/2017/10/171006124004.htm Le GM, Gomez SL, Clarke CA, Glaser SL, West DW. (2002). Cancer incidence patterns among Vietnamese in the United States and Ha Noi, Vietnam. Int J Cancer 102:412– 417. http://dx.doi.org/10.1002/ijc.10725. Shimizu H, Ross RK, Bernstein L, Yatani R, Henderson BE, Mack TM. (1991). Cancers of the prostate and breast among Japanese and white immigrants in Los Angeles County. Br J Cancer 63:963–966. http://dx.doi.org/10.1038/bjc.1991.210 Siegel, R. L., Miller, K. D. and Jemal, A. (2016), Cancer statistics, 2016. CA: A Cancer Journal for Clinicians, 66: 7–30. doi:10.3322/caac.21332 Urbaniak C, Cummins J, Brackstone M, Macklaim JM, Gloor GB, Baban CK, Scott L, O’Hanlon DM, Burton JP, Francis KP, Tangney M, Reid G. (2014). Microbiota of human breast tissue. Appl Environ Microbiol 80:3007–3014. http://dx.doi.org/10.1128/AEM.00242-14 Urbaniak C, Gloor GB, Brackstone M, Scott L, Tangney M, Reid G. (2016). The microbiota of breast tissue and its association with breast cancer. Appl Environ Microbiol 82:5039–5048. doi:10.1128/AEM.01235-16.