Browsing by Author "Zhou, C.K."
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Item Overall and abdominal obesity and prostate cancer risk in a West African population: An analysis of the Ghana Prostate Study(International Journal of Cancer, 2020-03-11) Yeboah, E.D.; Hurwitz, L.M.; Biritwum, R.B.; Tettey, Y.; Adjei, A.A.; Mensah, J.E.; Tay, E.; Okyne, V.; Truelove, A.; Kelly, S.P.; Zhou, C.K.; Butler, E.N.; Hoover, R.N.; Hsing, A.W.; Cook, M.B.Obesity has been associated with an increased risk of advanced prostate cancer. However, most studies have been conducted among North American and European populations. Prostate cancer mortality appears elevated in West Africa, yet risk factors for prostate cancer in this region are unknown. We thus examined the relationship between obesity and prostate cancer using a case-control study conducted in Accra, Ghana in 2004 to 2012. Cases and controls were drawn from a populationbased sample of 1037 men screened for prostate cancer, yielding 73 cases and 964 controls. An additional 493 incident cases were recruited from the Korle-Bu Teaching Hospital. Anthropometric measurements were taken at enrollment. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR) and prostate cancer, adjusting for potential confounders. The mean BMI was 25.1 kg/m2 for cases and 24.3 kg/m2 for controls. After adjustment, men with BMI ≥ 30 kg/m2 had an increased risk of prostate cancer relative to men with BMI < 25 kg/m2 (OR 1.86, 95% CI 1.11-3.13). Elevated WC (OR 1.76, 95% CI 1.24-2.51) and WHR (OR 1.46, 95% CI 0.99-2.16) were also associated with prostate cancer. Associations were not modified by smoking status and were evident for low- and high-grade disease. These findings indicate that overall and abdominal obesity are positively associated with prostate cancer among men in Ghana, implicating obesity as a potentially modifiable risk factor for prostate cancer in this region.Item TMPRSS2:ERG Gene Fusions in Prostate Cancer of West African Men and Ameta-Analysis of Racial Differences(American Journal of Epidemiology, 2017-06) Zhou, C.K.; Young, D.; Yeboah, E.D.; Coburn, S.B.; Tettey, Y.; Biritwum, R.B.; Adjei, A.A.; Tay, E.; Niwa, S.; Truelove, A.; Welsh, J.; Mensah, J.E.; Hoover, R.N.; Sesterhenn, I.A.; Hsing, A.W.; Srivastava, S.; Cook, M.B.The prevalence of TMPRSS2-ERG fusions in prostate cancer varies by race. However, such somatic aberration and its association with prognostic factors have neither been studied in a West African population nor been systematically reviewed in the context of racial differences. We used immunohistochemistry to assess ERG expression as the established surrogate of ERG fusion genes among 262 prostate cancer biopsies from the Ghana Prostate Study. Poisson regression with robust variance estimation provided prevalence ratios and 95% confidence intervals of ERG expression in relation to patients' characteristics. We found 47 of 262 (18%) prostate cancers were ERG-positive, and negative ERG staining was associated with higher Gleason score. We further conducted a systematic review and meta-analysis of TMPRSS2-ERG fusions in relation to race, Gleason score, and tumor stage, combining results from Ghana with 40 additional studies. Meta-analysis showed the prevalence of TMPRSS2-ERG fusions in prostate cancer to be highest in men of European descent (49%) followed by Asian (27%) and then African (25%). The lower prevalence of TMPRSS2-ERG fusions in men of African descent implies that alternative genomic mechanisms might explain the disproportionately high prostate cancer burden in such populations.