Study helps explain how malaria parasite might cause blood cancer

In collaboration with the Press Association

US scientists have uncovered how infection with a  malaria-causing parasite can increase the chances of immune cells developing into cancer.

“We need more research to work out the sequence of events in humans as the disease develops,” Professor Martin Rowe, Cancer Research UK

The way in which malaria increases the risk of a type of blood cancer called Burkitt’s lymphoma has remained a mystery for more than 50 years.

And the latest study, published in the journal Cell, offers one possible explanation. 

The researchers, based at The Rockefeller University in New York, made their discovery by studying malaria infections in mice. 

They found that the DNA of a type of immune cell known as a B lymphocyte became vulnerable to cancer-causing faults when exposed to long-term infection with the malaria-causing parasite Plasmodium.

Cancer Research UK’s Professor Martin Rowe, an expert in how infections can cause tumours, said the findings show early promise. 

“This is a very interesting and important study suggesting one way malaria might cause Burkitt’s lymphoma,” he said.

“The research was carried out in mice, so the finding doesn’t necessarily mean the same thing will happen when malaria infects humans. But the mouse experiments do closely mimic some of the key features of Burkitt’s lymphoma, so the results are very informative.”

During prolonged immune responses to malaria, the B lymphocytes multiplied extensively and continued to produce a protein called AID (activation-induced cytidine deaminase).

AID normally changes the DNA code of antibody genes to promote ‘shuffling’ of DNA, a crucial process that helps produce the wide variety of antibodies needed to fight the infection. 

The US team found that in the case of malaria-infected B cells, AID causes DNA rearrangements in other genes, including those involved in the development of cancer.

Dr Davide Robbani, lead author of the study at The Rockerfeller University, said AID was “a necessary risk.”

“You need AID to make potent antibodies to fight infection, but AID also causes collateral damage, leading to DNA breaks and mutations, thus increasing the odds of cancer."

But the team found that Burkitt’s lymphoma only developed in the mice’s immune cells when they lacked a second protein – called p53

“The mice in which malaria infection caused lymphoma were chosen for their lack of a key gene called p53, as this gene is also frequently missing in Burkitt’s lymphoma,” said Professor Rowe. 

“We need more research to work out the sequence of events in humans as the disease develops,” he said.

As well as malaria, cases of Burkitt’s lymphoma are also linked to infection with a virus called the Epstein-Barr virus. And Rowe stressed that these latest findings should be viewed alongside other studies to get a clearer picture of how the disease develops.

“We also need to understand the role of Epstein-Barr virus infections, which are also linked to the disease.

“It is important to realise that although chronic malaria and Epstein-Barr virus infections together increase the likelihood of developing Burkitt’s lymphoma, there are many other factors involved, and only a tiny number of people with these infections will actually get lymphoma,” he added.