The molecular nature of multiple tumour-associated antigens expressed by a Rauscher-MuLV induced leukaemia.

The identification of the molecules that bear the antigenic determinants recognized during an anti-tumour immune response is an important goal of tumour biology. It is now well established that most murine tumours express multiple tumour-associated antigens and in many cases it has been possible to show that these multiple antigens are expressed on completely different molecules. In the case of tumours induced by DNA and RNA viruses, certain virally encoded proteins may be tumour antigens. However, these tumours, like tumours of nonviral origin, also express other antigen-bearing molecules that are encoded by cellular genes. Frequently, the same tumour-associated antigen-bearing molecules are shared by all independently induced tumours of similar aetiology leading to the prediction that the expression of these antigenic molecules is linked to the molecular events necessary for tumour induction. Many of the nonviral tumour-associated antigen-bearing molecules purified to date are also found on normal tissues, but the normal metabolic function of these molecules and the alterations that render them antigenic are not yet understood.