New research has led to the conclusion that prostate and breast cancer is more deadly for African Americans than for whites. It has been reported that black men in the United States are around 60% more likely to develop prostate cancer than white men, and are more than twice as likely to die from the disease. Researchers have used “gene chips” to look for gene activity in prostate tumours, and found significant differences between the two sets of tumours in terms of the activity of over 160 genes, many of which are highly important in regulating the immune system. Given that these genes are involved in producing interferons, a defence against viruses in the body, the higher incidence of prostate cancer in African Americans could be due to a higher rate of infection (probably with an unknown, cancer causing virus).

African American women, on the other hand, are less likely to develop breast cancer that white women, but in blacks, the disease strikes younger people and is more likely to kill. It is suspected that differences in tumours may again be involved. Research found 65 genes with significantly different levels of activity between the tumours from blacks and whites. Unlike the prostate study, this research found no obvious link to the immune system. Most of these genes had not previously been linked to cancer suppression or tumour development.

What causes these differences between the races is not yet clear. Researchers believe that mutations in genes may be involved. An alternate suggestion is that the differences may be linked to chemical alterations, or epigenetic changes, to the DNA that regulates the genes’ activity. The long term goal is to identify new targets for drugs, which will hopefully be valuable for treating African Americans.

Brodie Grant-Taylor
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Article available at:
http://www.newscientist.com/article/dn13681-gene-activity-may-explain-cancers-racial-divide.html