BMC Cancer 2009, 9:397 http://www.biomedcentral.com/1471-2407/9/397 HUH PCA screening program, and the South Carolina PCA screening program (Table 1). The PCA patients and screening participants, recruited between 2001 and 2005, had a PSA and DRE. Subjects who had an abnormal PSA (>4.0 ng/ml) and/or irregular DRE underwent multiple core needle biopsies. Incident PCA cases in the current study were identified by an HUH urologist based on abnormal PSA (>2.5 ng/ml) and/or DRE as well as histo- logical findings following a radical prostatectomy. Inclu- sion criteria of controls were men with PSA levels ≤ 2.5 ng/ ml and/or normal DREs/biopsies. Tumor grade, ranging from 4-10, was collected for 62.0% of the cases (n = 129). Subjects (n = 216) were classified as current (n = 38), former (n = 71) and never (n = 107) smokers. All study participants had available DNA extracted from whole blood and provided written informed consent for partici- pation in genetic analysis studies under a protocol approved by the Howard University Institutional Review Board as well as from the HUH Division of Urology. evaluations of single and multi-locus genetic and environ- mental markers as indicators of PCA susceptibility within our population sample. Methods Study population Unrelated male residents (n = 1016) of Washington D.C. and Columbia SC, were considered for eligibility in the current PCA case control study. Study participants (n = 132) were not considered in the current study if they met one or more of the following exclusion criteria: (1) they were diagnosed with benign prostatic hyperplasia (n = 64); (2) had an abnormal prostate specific antigen (PSA) and digital rectal examination (DRE) (n = 11); and (3) had European ancestry based on a Global Ancestry score of < 25% (n = 70)[28]. Eligible men of African descent (i.e., self-identified African-Americans, East Africans, West Africans, and Afro-Caribbeans), including 208 patients (ages 41-91) and 665 healthy volunteers (ages 26-89), were recruited from the Howard University Hospital (HUH) Division of Urology PCA patient population, the Table 1: Patient and Tumor Characteristics Characteristics Number of Participants, n Age (yrs) Median (range) PSA in ng/ml n (%) < 4 ≥ 4 Gleason Score n (%) 4 5 6 7 8 9 10 Smokers n (%) Never Former Current Eversmokers n (%) No Yes Global West African Ancestry Median (SD) 0.791 (0.253-0.947) 0.718 (0.255-0.946) Abbreviations: PSA, prostate specific antigen aDifferences in frequencies were tested by a Chi-square test of heterogeneity (i.e., PSA ng/ml); Differences in age and Global West African Ancestry between cases and controls were tested using the Wilcoxon sum Rank test. Cases 208 65 (41-91) 43 (22.0) 152 (78.0) 17 (13.2) 15 (11.6) 33 (25.6) 40 (31.0) 6 (4.6) 14 (10.9) 4 (3.10) 62 (45.6) 51 (37.5) 23 (16.9) 62 (45.6) 74 (54.4) Controls 665 52 (26-89) 609 (94.4) 36 (5.6) 45 (20.8) 20 (25.0) 15 (18.8) 45 (56.3) 35 (43.8) p-valuea --- 0.0001 < 0.0001 0.162 0.130 0.020 Page 3 of 10 (page number not for citation purposes)