Scientists have identified a gene, called MNX1, that may account for the increased incidence of prostate cancer among African-American patients, according to a new study published in the journal Cancer Research.
The study, “MNX1 Is Oncogenically Upregulated in African-American Prostate Cancer,” supports the idea that certain genetic factors are responsible for differences in prostate cancer incidence among men from distinct ethnic groups. The findings suggest MNX1 could become a valuable biomarker for diagnosis.
“African-Americans have about one-and-a-half times the incidence and twice the mortality associated with prostate cancer of European Americans, and the reasons for this are not clear,” Michael Ittmann, MD, PhD, senior author of the study, said in a news release. Ittmann is a professor of pathology and immunology at Baylor University College of Medicine and the Michael E. DeBakey Department of Veterans Affairs Medical Center.
Together with genetics, socio-economic factors also account for the differences in disease occurrence. For instance, less access to healthcare services may mean less regular examinations and screenings for prostate cancer among African-American men.
To investigate genetic differences causing prostate cancer between African-American and European-American men, researchers analyzed the genetic profile of tissue samples from patients of those ethnic groups.
“We found 24 genes that were different between the African-American and the European-American prostate cancer datasets,” said Ittmann. “Some of the genes were less active in African-American prostate cancer, but we concentrated on those that were more active as they could potentially be oncogenes. MNX1 was at the top of the list,” he said.
MNX1 has been associated with infantile acute myeloid leukemia, a rare cancer of the bone marrow and lymph nodes. This gene codes for a transcription factor, which is a protein that activates the expression of other genes and leads to production of the correspondent proteins.
Compared with samples from healthy prostates, both African-American and European-American prostate cancer have increased activation of the MNX1 gene and, consequently, more MNX1 protein. But MNX1’s levels are significantly higher in the African-American group than in the European-American.
Researchers also found that increased activation of this gene was associated with higher lipid metabolism, a hallmark of aggressive prostate cancer, compared with normal tissue.
The researchers said the results obtained in this study may pave the way for the development of new therapeutic strategies for prostate cancer. Future therapies may include drugs already available to control lipid production, and exploring their effect in tumor growth. It also will be interesting to investigate whether MNX1 can be used as a biomarker for diagnosis of prostate cancer.
“The better we can understand different subsets of prostate cancer, for instance, prostate cancer from African-American men, the better we can treat them”, said Chad Creighton, PhD, one of the authors of the study and associate professor of medicine at Baylor. “A one-size-fits-all approach to treatment may not work for all patients,” he said.