The 11 TG-PCA3 STR allele was associated with a significant increase of prostate cancer risk at the allelic level (OR = 1.49; 95% CI 1.11–1.99; P = 0.008), while the TG-PCA3 12 repeats allele was associated with decreased prostate cancer risk (OR = 0.74; 95% CI 0.63–0.86; P < 0.0001). This evidence concerns the gene PCA3 and Familial prostate cancer.