Scientists say they have discovered that specific bacteria found in the intestines are major contributors to lymphoma, a cancer of the white blood cells in the immune system.

The researchers, from the Jonsson Comprehensive Cancer Center (JCCC) at the University of California in LA (UCLA), studied mice with ataxia-telangiectasia (A-T), a genetic disease that is associated with a high rate of B-cell lymphoma in humans and mice. Their study is published in The Journal of Cancer Research.

The human gut has around 100 trillion bacterial cells from up to 1,000 different species, the researchers say. They add that every person’s microbiome (the body’s bacterial make-up) is different as a result of the effects of diet and lifestyle, and the childhood source of bacteria.

From this, the scientists wanted to see whether the differences in people’s microbiomes would affect their risk of developing lymphoma, and whether changing the bacteria could reduce this risk.

The results were that mice who had a certain type of intestinal bacteria lived much longer before developing lymphoma than those with other types of bacteria, and also had less of the genotoxicity (gene damage) that causes lymphoma.

Robert Schiestl – professor of pathology and laboratory medicine, environmental health sciences and radiation oncology – says:

This study is the first to show a relationship between intestinal microbiota and the onset of lymphoma.

Given that intestinal microbiota is a potentially modifiable trait, these results hold considerable promise for intervention of B cell lymphoma and other diseases.”

From the study, the researchers were able to create a catalog of bacteria types that have “promoting or protective effects on genotoxicity lymphoma”. They say this could lead to the creation of combined therapies that could expand the cancer-protective bacteria while killing the cancer-promoting bacteria.

Lymphoma is a cancer that originates in immune system cells called lymphocytes. There are two types of lymphoma: Hodgkin lymphoma (also known as Hodgkin’s disease) and non-Hodgkin lymphoma (NHL). According to the American Cancer Society, NHL is one of the most common cancers in the US, with 1 in every 50 Americans at risk of developing the disease.

This study is the latest to offer potential developments in the treatment and prevention of lymphoma. For example, a study from researchers in Canada discovered a chemical compound that blocks the protein BCL6, which is found to cause cancer in around half of all non-Hodgkin lymphoma cases.