Breast cancer is one of the most common cancers in women around the world. Doctors have long known that many factors can affect the risk of developing this disease.
These include genetics, lifestyle, hormones, and environmental influences. Now, scientists have discovered a surprising new factor that may also play a role: bacteria from the mouth.
In a study published in the journal Cell Communication and Signaling, researchers from the Johns Hopkins Kimmel Cancer Center and the Bloomberg-Kimmel Institute for Cancer Immunotherapy found that a common oral bacterium may help start breast cancer and make it worse. The bacterium is called Fusobacterium nucleatum, and it is usually linked to gum disease.
Gum disease, also known as periodontal disease, is very common. It happens when bacteria build up in the mouth and cause inflammation of the gums. If not treated, it can lead to bleeding gums, pain, and even tooth loss. Scientists have already found links between gum disease and other health problems, including heart disease and some types of cancer.
In this new research, scientists wanted to understand whether bacteria from the mouth could affect breast tissue. They focused on Fusobacterium nucleatum because earlier studies had already connected it to cancers such as colorectal cancer.
The researchers discovered that this bacterium can enter the bloodstream from the mouth. Once in the blood, it can travel to other parts of the body, including the breast. When it reaches breast tissue, it may trigger inflammation and cause changes in cells that are linked to cancer development.
To study this, scientists used both animal models and human breast cancer cells in the laboratory. When they introduced the bacterium directly into breast tissue, they observed important changes.
The cells began to grow more quickly than normal, and some of them changed their structure. These early changes are not yet cancer, but they can increase the risk of cancer forming later.
At the same time, the presence of the bacterium caused inflammation and damage to the cells’ DNA. DNA is the genetic material that controls how cells grow and function. When DNA is damaged, it can lead to mutations, which are changes that may cause cancer.
The study also showed that the bacterium can make existing cancer more aggressive. When it entered the bloodstream in animal models, tumors grew faster and were more likely to spread to other organs, especially the lungs. This process, known as metastasis, is one of the most dangerous aspects of cancer.
The researchers looked more closely at how this bacterium causes damage. They found that it activates a DNA repair process in cells. While this process helps fix broken DNA, it is not always accurate. It can introduce mistakes, which may increase the risk of cancer.
The team also found that even a short exposure to the bacterium increased the level of a protein called PKcs. This protein was linked to more movement of cancer cells, stronger ability to invade nearby tissue, and greater resistance to treatment such as chemotherapy.
Some cells appeared to be more vulnerable than others. In particular, cells with mutations in a gene called BRCA1 were more easily affected. The BRCA1 gene normally helps repair DNA and protect cells from becoming cancerous. When this gene is mutated, the risk of breast cancer is already higher.
In the study, BRCA1-mutant cells had higher levels of a special surface molecule that made it easier for the bacteria to attach and enter the cells. As a result, these cells absorbed more of the bacteria and kept it inside for longer periods. This led to more DNA damage and stronger cancer-promoting effects.
The researchers believe that this finding is important because it shows how different risk factors can work together. A person may already have a genetic risk, such as a BRCA1 mutation, and the presence of harmful bacteria may increase that risk even further.
Although the results are concerning, the researchers stress that more studies are needed to understand how this works in real patients. It is not yet clear how often this happens or how strong the effect is in everyday life.
However, the study highlights the importance of good oral health. Taking care of the teeth and gums may not only prevent dental problems but could also play a role in overall health, including reducing the risk of serious diseases.
Overall, this research opens a new area of study. It suggests that bacteria in the body, especially those from the mouth, may have a bigger impact on diseases like cancer than previously thought. Future studies will need to explore whether improving oral hygiene or treating gum disease can help lower the risk of breast cancer or slow its progression.
These findings provide a new perspective on cancer prevention. They remind us that the body is highly connected, and health in one area can affect health in another. While more research is needed, maintaining good oral hygiene remains a simple and important step for overall well-being.
If you care about breast cancer, please read studies about how eating patterns help ward off breast cancer, and soy and plant compounds may prevent breast cancer recurrence.
For more health information, please see recent studies about how your grocery list can help guard against caner, and a simple way to fight aging and cancer.
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