Cluster 181: psa rising apart value ng week progression ml values prostate 
Cluster 477: psa prostate specific ng antigen ml days serum cancer value 
Cluster 1172: ng psa ml level prostatectomy serum nadir prostate vitamin post 
Cluster 1387: gleason psa prostate score risk ng stage ml tb intermediate 
Cluster 2396: measure psa reference nd rising days value taken rises initial