A mutation that confers resistance to malaria is now linked to cancer metastasis. This finding illustrates evolutionary changes may sometimes be a double-edge sword.
Despite the best efforts, parts of Africa have disproportionately high rates of malaria. For example, more than 90 percent of malarial cases were documented in Sub-Saharan Africa alone. The disease is attributed to a large percentage of deaths.
The high rate of malaria acts as an evolutionary pressure, selecting for individuals with unique mutations that confer resistance to this disease. In particular, people in West Africa and sub-Saharan Africa are more likely to have an alternate version of the Duffy Antigen Receptor (DARC) gene than any other population. The widely prevalent version of the DARC gene “makes most Africans less susceptible to a type of malaria caused by [the parasite] Plasmodium vivax,” said Geoffrey Siwo, a scientist at the IBM Research Africa in Johannesburg.
In studying the interactions between malaria and other diseases, Siwo and his team found a paradoxical, if not tragic, link between the DARC mutation and cancer. Specifically, they found that people who have the DARC variation and are protected from malaria were less likely to survive cancer. In other words, the variation that confers malarial resistance could somehow be helping the spread of cancer.
For the study, Siwo and his team concentrated on breast cancer. According to the International Agency for Research on Cancer (IARC) and World Health Organization, breast cancer rates in Africa range from around 20 per 100,000 women to as high as over 40 per 100,000 women.
"If this variant does play a role in cancer metastasis, it would be an example where a genetic variant which rises to high frequency due to protection from malaria may also be associated with disease risk", said Sarah Tishkoff, a professor at the University of Pennsylvania, who was not associated with the study.
For Siwo though, the cup is half-full. "The knowledge that low expression of DARC might influence breast cancer outcomes, especially in some breast cancer patients means that in future it could potentially be used for personalizing therapy or precision medicine," he says.
Thinking more globally, future research into how the DARC genetic variation could be driving cancer growth may open new avenues for therapy that we’ve yet to uncover.
Additional sources: CNN