There are several synonyms for the term "tumor antigen," which refers to a protein that is expressed by cancer cells and can stimulate an immune response in the body. One common synonym is "cancer antigen," which is often used interchangeably with tumor antigen. Other synonyms include "oncofetal antigen," which is a type of tumor antigen that is expressed by both fetal and cancer cells, and "neoantigen," which refers to a newly formed antigen that arises as a result of genetic mutations in tumor cells. Understanding these synonyms can help researchers and clinicians better communicate about cancer diagnosis and treatment, as well as facilitate the development of new immunotherapies that target tumor antigens.