Strong Tiam1 overexpression (i.e. ⩾3.5-fold) in prostate carcinomas relative to the respective benign prostatic epithelium was statistically significantly associated with disease recurrence (P=0.016), the presence of lymph vessel invasion (P=0.031) and high Gleason scores (GS) (i.e. ⩾7) (P=0.044). Here, TIAM1 is linked to prostate carcinoma.