Lynch syndrome and screening are described in the “JSCCR guidelines 2019 for the treatment of colorectal cancer,” “JSCCR Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer,” “Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, Third Edition” and “Guideline for Gynecological Practice in Japan.” (Colorectal cancer-related guidelines also include a description of PD-1 inhibitors). The gene discussed is PDCD1; the disease is Lynch syndrome.