If genetic mutations interfere with these proper behaviors, they can lead to the breakdown of cellular cooperation and the emergence of cancer. Cancer cells can be considered as cellular cheaters because they do not obey the rules of cooperative behavior. They mutate uncontrollably, avoid cell death (being destroyed) and take up excessive resources at the expense of other cells. Cancer begins to grow in the body as soon as these cheater cells create other cells like themselves. Cancer is basically a problem of many cells living together in one body structure. This is pretty much the case since the origin of multicellular life. This means that cancer suppression mechanisms have been evolving over hundreds of millions of years to help keep cancer cells under control.
Cells monitor themselves for mutations and when necessary induce cell death, also known as ‘apoptosis’. Cells also monitor their neighbors (cells) for evidence of abnormal behaviour, sending signals to abnormal cells to induce ‘apoptosis’. In addition, the body’s immune system monitors tissues to destroy cancer cells. Cells that are able to avoid detection, avoid apoptosis, and rapidly replicate themselves have an evolutionary advantage within the body over normally behaving cells. This process inside the body, called ‘somatic growth’, prompts cancer cells to grow and make people sick. Microbes may affect cancer risk by changing the way the body’s cells interact with each other.
Certain microbes may protect against cancer by maintaining a healthy environment in the gut, reducing inflammation and DNA damage, and even directly limiting tumor growth. Cancer-protective bacteria such as Lactobacillus pentosus, Lactobacillus gasseri and Bifidobacterium bifidum are found in the environment and various foods, and can live in the gut. These bacteria promote cooperation between cells and limit the act of cheating cells by strengthening the body’s cancer defenses. Other bacteria can promote cancer by inducing mutations in healthy cells that make ‘cellular cheaters’ more likely to emerge and outcompete helpful cells. These can release toxins that damage DNA, alter gene expression, and increase the spread of tumor (cancer) cells.
While what you eat determines the amount of cancer-inducing and cancer-preventing bacteria inside your body, we recognize that the bacteria we consume and foster is an important component of a healthy diet. Beneficial microbes are commonly found in fermented and plant-based diets, which include foods such as vegetables, fruits, yogurt and whole grains. These foods are high in nutrition and contain microbes that enhance the immune system’s ability to fight cancer and reduce overall inflammation.
High-fiber foods are prebiotic in the sense that they provide resources that help beneficial bacteria thrive and subsequently provide benefits for cells. Many cancer-fighting bacteria are abundant in fermented and high-fiber foods. In contrast, harmful microbes can be found in highly processed and meat-based diets. Bacteria can enhance or inhibit the cooperation of the body’s cells to prevent cancer. We believe that purposefully developing bacteria that promote cooperation between our cells may help reduce cancer risk.
(Jisel Marquez Alcaraz and Athena Actepis of Arizona State University)