Prostate cancer is the second most common cause of cancer worldwide after lung cancer. Diet and lifestyle play a crucial role in prostate cancer biology and tumourigenesis. Dietary agents have gained considerable attention. Human prostate-specific antigen (PSA or KLK3) is an important marker for the diagnosis and management of prostate cancer. This is an androgen-regulated glycoprotein of the kallikrein-related protease family secreted by prostatic epithelial cells. Its physiological function is to cleave semenogelins in the seminal coagulum.