Distribution of cancer-related HERV papers by year. Articles with a single cancer focus were sorted by year of publication and used for visualization. (A) For distribution ratios, gastrointestinal cancer and colorectal cancer were summarized to digestive cancers, leukemia and lymphoma to blood cancer, and lung cancer, uterus cancer, thyroid cancer, myeloma, bone and joint cancer, cervical cancer, soft tissue cancers including heart cancer, urinary bladder cancer, other genital cancer, and other oral cavity and pharynx cancer to other cancer. (B) The seven most studied cancers in HERV-focused articles were evaluated for their publication distribution. Publication density was plotted against the year of publication.