Despite significant advances in our understanding of the mechanism of action of Id1 in prostate cancer, such as regulation of p16 [26, 27], EGFR [28], androgen independence, prostate-specific antigen expression [29] and its role in cell proliferation [23] and metastasis [30], the expression Id1 has remained controversial. The gene discussed is KLK3; the disease is Familial prostate cancer.