CDK5 and Familial prostate cancer: To uncover potential associations between altered drebrin expression and clinical outcome in prostate cancer we interrogated data (mRNA expression changes and copy number variations) from the publically available MSKCC Prostate Cancer Genomics Data Portal data set.19 We found that both increased mRNA expression and copy number gain of drebrin, Cdk5 and Cdk5R1 (p35, the regulatory subunit of Cdk5), occur significantly more frequently in prostate cancer metastasis samples (n=37) than in primary (that is, organ-confined, n=179) prostate cancer samples (Supplementary Figure S2).