Unlike humans, cancer is rare in other primates. In 1901-1932, scientists performed autopsies on non-human primates that were dying at the Philadelphia Zoo. Tumors were found in only eight of the 971 primates.
A study by geneticists at the Memorial Sloan Kettering Cancer Center in New York City appeared in Cell Reports, reports NewScientist, to try to understand why a person has a much higher risk of cancer. During the study, they compared the genes of humans and 12 species of other primates. It turned out that the difference in the version of the BRCA2 gene, which has mutated in us since humans became an independent species, may be the reason.
The BRCA2 gene is involved in DNA repair and suppresses the development of tumors. In humans, a single mutation in this gene resulted in a 20% drop in the ability to regenerate DNA. This may explain our high incidence of cancer.
The role of this gene in the development of tumors was known before: people with certain variants of BRCA2 that suppress its reparative activity are even more at risk of developing cancer, especially breast and ovarian cancer.
Why BRCA2 evolved to be less active in humans than in other primates is unknown. But there is a possibility that reduced BRCA2 activity is associated with increased fertility: women with oncogenic BRCA2 variants have an easier time getting pregnant. That is, we received an increase in the birth rate in exchange for the fact that we began to get sick with cancer more often.
Perhaps in the future, when it becomes possible to edit genes, the human BRCA2 gene can be rewritten and made similar to the gene of non-human primates, thereby saving people from cancer.