Such men may be less likely to be diagnosed with prostate cancer overall, and in particular with early prostate cancer, because they have lower PSA concentrations (perhaps due to an increased blood volume since the total amount of PSA in blood does not differ by body mass), are less likely to undergo a biopsy, and are also likely to have larger prostates, making cancer detection more difficult [37]. This evidence concerns the gene KLK3 and prostate cancer.