ABSTRACT

A number of properties distinguish tumor from normal cells, including their invasiveness, loss of growth contact inhibition, and lack of response to regulation. In addition, there is considerable evidence for quantitative and qualitative differences in antigens associated with normal versus tumor cells. These antigens can be divided into tumor-specific antigens (TSA)—those unique to tumor cells—and tumor-associated antigens (TAA)—those also found on some normal cells. Another classification system is based on the origin or nature of the antigens and includes viral, chemical, oncofetal, and differentiation antigens.