Prostate and breast cancer are more deadly for African Americans than for whites. Now it seems that differences in the activity of key genes may be partly to blame.
Black men in the US are around 60% more likely to develop prostate cancer than their white counterparts, and are more than twice as likely to die from the disease.
In large part, these differences are thought to be due to socioeconomic factors such as access to healthcare. But at the annual meeting of the American Association for Cancer Research (AACR) in San Diego on 15 April, Tiffany Wallace of the US National Cancer Institute in Bethesda, Maryland, argued that biological differences between the tumours of blacks and whites are also involved.
Wallace and her colleagues used "gene chips" to scan for gene activity in prostate tumours removed from 33 African-American and 36 white patients. There were significant differences between blacks and whites for the activity of more than 160 genes, many of which were involved in regulating the immune system.
These differences could simply reflect greater inflammation in the tumours of African Americans. But given that some of the genes are involved in the production of interferons, one of the body's defences against viruses, the higher incidence of prostate cancer in African Americans could be due to a higher rate of infection with an unknown cancer-causing virus. To test this possibility, the researchers are now looking for viral genes in prostate tumour samples.
