Racial variation in CAG repeat lengths within the androgen receptor gene among prostate cancer patients of lower socioeconomic status.

Abstract

To evaluate (1) whether there were racial differences in the androgen receptor gene CAG repeat length and in clinical or laboratory attributes of prostate cancer at the time of diagnosis; (2) whether there were differences in race, Gleason score, prostate-specific antigen (PSA) level, and stage at diagnosis by androgen receptor gene CAG repeat length; and (3) whether sociodemographic, clinical, and laboratory based factors might be associated with advanced-stage prostate cancer. To our knowledge, our study is the first to report on CAG repeat lengths in a cohort of prostate cancer patients, which includes large numbers of African-American men. CAG repeat lengths on the androgen receptor gene were evaluated for 151 African-American and 168 white veterans with prostate cancer. The chi(2) test, t test, and logistic regression analyses were used to evaluate the associations between CAG repeat lengths and race, stage, histologic grade, and PSA levels at diagnosis. The mean age of the cohort at the time of diagnosis was 68.7 years. At presentation, 42.0% had stage D prostate cancer, 26.5% had Gleason scores of 8 to 10, and 53.0% had PSA levels >/= 10 ng/dL. Mean androgen receptor gene CAG repeat length for white veterans was 21.9 (SD, 3.5) versus 19.8 (SD, 3.2) for African-American veterans (P =.001). Men with shorter CAG repeats were more likely to have stage D prostate cancer (P =.09) but were not more likely to have a higher PSA concentration or Gleason score. In this cohort of men with prostate cancer, short CAG repeat length on the androgen receptor gene was associated with African-American race and possibly with higher stage but not with other clinical or pathologic findings.