A new study from Australia suggests B cells, a type of white blood cell, undergo spontaneous changes that could lead to cancer if the immune system does not carry out regular checks and kill them before they form tumors.

In the journal Nature Medicine, Dr. Axel Kallies, of the Walter and Eliza Hall Institute in Parkville, Victoria, and colleagues report that the immune system removes errant B cells before they become cancerous.

“Each and every one of us has spontaneous mutations in our immune B cells that occur as a result of their normal function,” Dr. Kallies says.

If cancerous B cells go on to form tumors they develop into B cell lymphomas, also known as non-Hodgkin’s lymphomas.

The researchers found T cells of the immune system carry out regular checks to find cancerous and pre-cancerous B cells.

They made the discovery while investigating how B cell lymphomas arise, and they believe this regular surveillance by the immune system is probably why there are not as many cases of B cell lymphomas in the population, given how often the spontaneous changes occur.

They suggest the discovery offers the prospect of an early-warning test that could find patients at higher risk for developing B cell lymphomas. This could lead to treatments that prevent the tumors growing in the first place.