Biological factor may be linked to prostate cancer racial disparities

Abstract

The disparities in incidence and mortality between African American and non-Hispanic white male patients with prostate cancer may be partially explained by a biological factor, according to researchers at the Medical University of South Carolina (MUSC) in Charleston. African American men in the United States are 1.5 times more likely to develop prostate cancer and more than twice as likely to die from it as non-Hispanic white men, according to the American Association for Cancer Research (AACR). David Turner, PhD, assistant professor in the department of pathology and laboratory medicine at MUSC, and colleagues say that they have identified a potential relationship between sugar-derived metabolites and cancer that may provide a biological link with socioeconomic and environmental factors known to contribute to prostate cancer disparities. He presented their findings at the AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, held December 6 to 9, 2013, in Atlanta, Georgia. As people use sugars that are consumed for energy, they create waste products or metabolites, known as advanced glycation end products (AGEs). The metabolites accumulate as people age and have been implicated in a variety of diseases, including diabetes, heart disease, and Alzheimer's disease. They also cause inflammation and chemicals known as reactive oxygen species, both of which can cause cancer. Dr. Turner's team found that AGE levels were highest in African American men with prostate cancer, likely because of obesity, poor eating habits, and an inactive lifestyle, all factors that are more evident among African Americans than non-Hispanic whites. They hypothesize that this link may explain the disparities in the disease incidence and mortality. To explore their hypothesis, they examined circulating intratumoral AGE levels in 16 African American and 16 non-Hispanic white men with prostate cancer. They found that AGE levels were higher in serum from patients with cancer compared with individuals without cancer. When analyzing AGE levels in prostate tumor samples, levels were highest in tumor samples from African American patients. Further, AGE levels in prostate tumors correlated with levels of a molecule to which AGEs bind to mediate their effects, known as receptor for AGE (RAGE). Dr. Turner's team hypothesizes that the AGE-RAGE signaling pathway promotes prostate cancer and that increased AGE accumulation may affect disparities in the disease. The article “Screening Debate” in the March 15 issue of CancerScope included an incorrect image of James E. Allison, MD, clinical professor of medicine emeritus in the division of gastroenterology at the University of California, San Francisco. His correct image appears to the left.