A preliminary database already exists containing information characterizing genes that are differentially expressed in tumor cells as opposed to those typically found in non-neoplastic tissue. Deleterious reactions are frequently generated by interactions between neoplastic cells and the immune system response apparatus. These interactions are capable of generating tumor growth factors, angiogenic factors, and immunosuppressive components. Tumor-associated immunosuppression is little understood, yet clinicians must learn to control this mechanism and develop means of dealing with it. Helpful investigatory areas would include characterization of the underlying mechanisms, implications for the natural history of the tumor, and consequences of the immunosuppressive reaction for the immunotherapy of the tumor.
Tumors are heterogeneous with regard to antigen expression.
Heterogeneity needs to be understood in each tumor so that as many as three or four individual molecular antigenic species may be targeted at one time. Similar clinical consortia for immunotherapy, especially for Phase I and II trials, are needed to expedite and standardize approaches. Human trials are more important than animal studies. For example, cytokines are species specific, and human cytokines can be evaluated only in primate systems. Workshops may be necessary for implementation.