Gene variants in black men linked to early prostate cancer

Genetic variants have been identified in some black men which may be linked with early-onset prostate cancer.

Prostate cancer is the most commonly diagnosed cancer in adult men in the United States. Black men are more likely to be affected than their counterparts in other ethnic groups, and they are likely to have worse outcomes when they do develop prostate cancer. However, most previous research into the genetic causes of prostate cancer has focused on white men, and there has been a shortage of data from black participants. Researchers in Michigan have now identified some genetic variants that could be linked to early-onset prostate cancer in some black men.

'The objective of this study was to examine the prevalence and spectrum of known mutations in cancer susceptibility genes in primarily DNA damage response pathways in African American men diagnosed with early-onset prostate cancer' said study author Jennifer Beebe-Dimmer, professor of oncology at Wayne State University, Detroit, Michigan. 'Our knowledge about the importance of these genes in black men with prostate cancer lags far behind our knowledge in men of European descent.'

Black men have the highest incidence of prostate cancer among any population group in the USA, and are twice as likely to die from the condition. It has been observed that black men diagnosed with early-onset prostate cancer have higher age-specific mortality rates. Black men are also more likely to have metastatic disease at diagnosis.

The reasons behind the disproportionately poor outcomes for black men could be varied, with both biological and nonbiologic influences. While socioeconomic differences, such as access to healthcare, are known to play a significant role in causing the poorer outcomes seen in black men, prostate cancer has strong evidence of heritability, particularly in early-onset cases.

To investigate a potential link between genetic variants found in black prostate cancer patients researchers at Wayne State and the Barbara Ann Karmanos Cancer Institute, Detroit, looked at parts of the genome known to be responsible for DNA repair. They discovered 26 unique variants in 14 genes in about four percent of the 743 black men in the cohort who had prostate cancer under the age of 62 that authors said could be linked to prostate cancer.

These variants were associated with a higher likelihood of being diagnosed with metastatic cancer, and a higher level of prostate-specific antigen, a marker known to be associated with prostate cancer. This study builds on the previous findings of this and other groups, who have found that mutations in the gene HOXB13, involved in DNA repair, have been linked with early-onset prostate cancer and a strong family history of the condition.

As Professor Beebe-Dimmer explained, 'Mutations in the genes identified in this study not only help us to understand the underlying biology of prostate cancer in African American men, but our new knowledge of these mutations may also be used in the development and use of targeted treatments, as well as screening for earlier detection of disease in unaffected family members.'

The study is published in JCO Precision Oncology.