The concept of immunologic responses against tumors is currently under intense scrutiny throughout the world. The evidence for the existence of tumor-specific transplantation antigens (TSTA) and specific immune reactions to them in experimental animals is overwhelming. The available data concerning human tumors are controversial. The reason for this is partially that antigens detectable on human tumors by in vitro assays have not been biologically characterized. In other words, we do not know if the antigens on human tumors are acting as the targets for immunologically mediated rejection processes in vivo. It was the purpose of this workshop to bring experimental tumor immunologists and clinical oncologists together in order to disclose facts and limits in tumor immunology. Clinicians were to learn how shaky the ground becomes once the experimentalist looks beyond the edge of the mouse cage. Tumor biologists heard the clinicians' urgent cry for controlled randomized trials of immunotherapy which thus reflects clearly that immunotherapy in its present form without knowledge of dose-effect-relationship does not work. Nobody would deny that the problem of human cancer smells of immunology, but since we are just about to taste it the essential ingredient might be different. In other words one might look at present rather at immunological epiphenomena than at mechanisms of tumor immul1lty operating in vivo. This problem was among others a central issue of this workshop.

I. Pathophysiologic Aspects of Tumor Development

Cellular Kinetics of Malignant Tumors
Fetal Patterns in Adult Rat Liver Undergoing Reparative and Neoplastic Growth
Immunologic Studies on Rat Bowel Carcinomas
Discussion
II. Clinical Significance of Immunologic Tests for Tumor Diagnosis
1. Tumor-Associated Antigens
Clinical Significance of Carcinofetal Antigens with Special Reference to CEA, AFP, and Related Substances
Immunodiagnosis of Gastric Cancer and Related Diseases; Deletion, Neoantigen, and Nonspecific Factors
Humoral and Cellular Immune Reactions to CEA
Tumor-Associated Antigens in Bronchogenic Carcinoma
Tumor-Associated Antigens and Immunity in Prostatic Carcinoma
Expression of Tumor-Associated Surface Antigens and Their Correlation to Parameters of Malignancy in Human Malignant Melanoma
Discussion
2. Cell-Mediated Immune Reactions
Correlation Between Nonspecific Immune Competence and Clinical Outcome of Breast, Colon, and Stomach Cancer
Immunocompetence Testing in Patients with One of the Common Operable Cancers - A Review
Significance and Mechanism of T-Cell Depression in Cancer
Cell-Mediated Immune Reactions in Patients with Colon Carcinoma
Significance of Spontaneous Lymphocyte-Mediated Cytotoxicity (SLMC) in Cancer Patients and Control Persons
Human Tumor-Lymphocyte Interaction in Vitro: Comparison of the Results With Autologous Tumor Stimulation (ATS) and Lymphocytotoxicity (ALC)
Lymphocyte Cytotoxicity in Melanoma Patients Undergoing Immunotherapy
Prediction of Recurrent Melanoma by Variations in the Strength of Anti-Tumor Immunity
Tumor Diagnosis Using Electrophoretic Mobility Test (EMT)
Discussion
Discussion
III. Immunotherapeutic Approaches
The Role of Immunotherapy in the Treatment of MalignantMelanoma
Tumor Immunotherapy - Experimental Evaluation and Clinical Prospects
Adjuvant Immunotherapy of Stage II Malignant Melanoma: Autologous Tumor Antigen Plus BCG
Search for the Role of Immunotherapy with Corynebacterium Parvum Intrapleurally in Operable Bronchial Non-Small-Cell Carcinoma The Ludwig Lung Cancer Collaborative Study Group
Discussion
Quantitative and Functional Studies of Lymphocyte Subpopulations During Adjuvant Chemo(immuno)therapy in Patients With Breast Cancer
Discussion
Interaction Between Levamisole and an Immunoregulatory Serum Component: Possible Mode of Action of Levamisole as an Immune Modulating Substance
Role of an Immunoregulatory Serum Component in Human Mixed Lymphocyte Reaction
Role of a Serum Component in Regulating the Growth of a Murine Lymphoma
IV. Special Procedures in Cancer Therapy - Effects on the Immune Status
Influence of Hyperthermia on the Immune Status: Experimental Basis and Clinical Application in Cancer Patients
Immunologic Phenomena Induced by Hyperthermia in Normal and Tumor-Bearing Hosts and Their Relevance for Cancer Therapy
Discussion
Immunologic Phenomena Induced by Cryosurgery
Clinical and Immunologic Results of Cryosurgery in Patients With Rectal Cancer
Parenteral Hyperalimentation as an Adjunct to Cancer Therapy in Patients with Colorectal Tumors
Discussion
V. Summing Up
Summing Up.