Cancer, one of the greatest worldwide public health issues, remains the leading cause of death in some developing countries.[1–3] Even though a long-term survival rate of breast and colorectal cancer has been increased significantly in most developed countries, other types of cancers and sarcomas are still fatal such as liver and lung cancer.[3,4] Searching tumor biomarkers for diagnosis, treatment, and prognosis is the breaking point of clinical cancer research, such as alpha fetal protein in liver cancer and prostate-specific antigen in prostate cancer.[5]. Here, KLK3 is linked to cancer.