A group of 54 exceptional responders (ERs) to cancer treatment across a variety of cancers and treatments were compared to typical cancer patients using previously defined polygenic risk scores (PRS) for multiple autoimmune-related diseases including type 1 diabetes, hypothyroidism, psoriasis, rheumatoid arthritis, multiple sclerosis, and inflammatory bowel (IBD) disease. Most of the ERs were not treated with checkpoint inhibitors and included a broad array of tumor types. Significantly elevated PRS scores were found between ERs relative to typical cancer patients in type 1 diabetes, hypothyroidism, and psoriasis. IBD PRS scores were significantly decreased in the ERs.