KLK3 and colorectal cancer: On the other hand, breast cancer screening of women age 45–54 years by annual or biennial mammogram, colorectal cancer screening by fecal immunochemical test or colonoscopy from the age of 50 years, and prostate cancer screening by prostate-specific antigen test with or without digital rectal examination from the age of 50 years are widely accepted guidelines proposed by national and international guidelines (5–11).