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First experience is presented concerning the diagnostic utility of serum neopterin determinations in cancer care. The data refer to single measurements (198 sera) and follow-up studies (30 gynecological cases) of the neopterin level of patients suffering from bowel carcinomas, mammary carcinomas, and gynecological disorders. The outcome reveals that single values do not essentially add to the diagnostic result obtainable by conventional markers. Therefore, the consistent follow-up of the neopterin level is recommended. As exemplified for a series of gynecological patients, repeatedly elevated serum neopterin values after therapeutic intervention indicate a worse prognosis than values remaining within the physiological range. These conclusions need to be more firmly established by extended observation time and a greater number of cases. To make better and reliable use of neopterin in cancer diagnosis, it is necessary to analyse the immunological background of the altered neopterin synthesis (or shedding) in malignant diseases.

KCl extracts (3 M) from human fetuses were tested by macrophage electrophoretic mobility (MEMB), leukocyte migration inhibition, and/or leukocyte adherence inhibition techniques against lymphocytes-leukocytes from tumor-bearing humans and control persons. A positive MEMB test was found in 209 of 284 (73%) patients with various types of clinically manifest tumors. Only 15 of 134 (11%) controls gave a positive reaction by the MEMB test. Leukocyte migration was significantly inhibited in 48 of 64 (75%) tumor patients, and leukocyte adherence was significantly inhibited in 40 of 50 (80%) tumor patients versus 7 of 50 (14%) and 10 of 54 (19%) in the corresponding controls. Lymphocyte reactivity to fetal extracts is also detectable in inbred XVII/Bln, CBA/Bln, and C3H/Bln mice bearing spontaneous or transplanted tumors of different etiology. Human and mouse fetal extracts gave cross-reactions. Lymphocytes from tumor-bearing mice were reactive against fetal extracts from the cow, pig, sheep, guinea pig, cat, and chicken. Mice bearing benign skin warts induced by 7,12-dimethylbenz[a]anthracene (DMBA) as well as DMBA-treated mice without visible skin lesions gave a positive MEMB test. Likewise, pregnancy is associated with lymphocyte reactivity to fetal extracts.

Theoretical aspects are considered on the requirements of immunological cancer tests. The criteria of clinical applicability are: Specificity, sensitivity, information with respect to tumour localisation. Immunodiagnostic tests cover the following areas: Early diagnosis on the basis of screening of the whole population or of risk groups, differential diagnosis, detection of relapse or metastases, prognosis. Experimental results are presented on a test for tumour detection. In a blind test study patients with clinically manifest tumours were recognized in about 80--90%, when using human fetal extract as antigen in the macrophage-electro-phoretic-mobility technique.

Purification of tumour-associated antigenic material from the ascites sarcoma cells was attempted by extraction with 3 M KCl and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The antigenic activity was assayed in the macrophage-electrophoretic-mobility (MEM) test. Extraction of whole tumour cells with 3 M KCl results in preparations with low antigenic activity which on SDS-PAGE show a very heterogenous composition of more than 20 protein bands. On comparison of the antigenic activity of different subcellular fractions obtained by differential centrifugation of the homogenate, the antigenic activity could be alloted to the cell membrane fraction. With this cell membrane fraction, three extraction media -- 3 M KCl, 2% Triton X-100, and 5% sodium cholate -- were tested for their ability to selectively extract the antigenic membrane proteins. The Triton X-100 treatment solubilized the greatest amount of membrane protein. Both Triton X-100 and sodium cholate, however, produced very heterogeneous protein extracts. In contrast, 3 M KCl selectively extracted three membrane components: a glycoprotein of high molecular weight and two low-molecular-weight carbohydrate-free proteins. Removal of the KCl in the presence of Triton X-100 precipitates the carbohydrate-free proteins, while the glycoprotein remains in solution. Testing the components of the KCl-extracts in the MEM-test after isolation by preparative SDS-PAGE revealed antigenic activity only with the glycoprotein component.

Tumor-bearing mice show a cellular sensitization to fetal antigens as detected by the macrophage electrophoretic mobility (MEM) test. Sensitization is independent of etiological and histological tumor factors. An identical state of sensitization can be found after application of chemical carcinogens (N-methyl-N-nitrosourea, benz(a)pyrene or 7,12-dimethylbenz(a)anthracene) before the tumors have developed. The results indicate that the effect is dose-dependent.

After passing normal mouse spleen cells through columns of a weakly basic ion-exchanger, the percentage of cells with B cell-typical electrophoretic mobility (EPM) is 90% after fractionation at pH 8.0 and 10--20% at pH 5.0. However, the characterization of fractionated cells with regard to theta-antigen as well as graft-versus-host reaction shows that separation of T- and B-lymphocytes had not occurred. After incubation of the separated cells for 2 h at 37 degrees C the EPM returned to that of unseparated cells. It appears that the net charge of T- and B-lymphocytes is changeable depending on pH, temperature and separation material.

The number of tumor markers used clinically has grown rapidly in recent years. The applicability of these substances to the improvement of cancer diagnosis is reviewed. The practical utility of most of the available markers is severely limited by their insufficient specificity and sensitivity. It is emphasized that, at present, the early diagnosis of common tumors by means of screening with specific markers is practically impossible. The suitable markers rather promise to be useful in the postoperative care of cancer patients, especially with respect to the estimation of the therapeutical success, the risk of metastatic processes, and the prognosis. The recently introduced monoclonal antibodies may assist in reaching a higher level of diagnostic statements. The markers CA 12-5, CA 15-3, CA 19-9, CA 50, TPA, and Neopterin are considered in detail.

Beads of calf serum proteins (CSB) with antigen-antibody complexes or antigen by activation with glutaraldehyde were used as immunoadsorbents for the fractionation of mouse lymphocytes. T-lymphocytes could be separated by this method with high purity. The precursors of antibody-forming cells were completely eliminated from spleen and bone marrow cell suspensions. The unspecific binding of lymphocytes to CBS or Sepharose was similar and not selective for T or B lymphocytes.

Soluble extracts were prepared by the 3 M KC1 method from human mouse fetuses at different stages of development. As shown by macrophage electrophoretic mobility and by leukocyte migration inhibition tests a high percentage of pregnant women is sensitized to components of these extracts. The testing of pregnant mice of an inbred strain gave similar results. The available data support the view that some kind of cellular sensitization to fetal antigen may occur during pregnancy.

Extracts were prepared by the 3M KCl method from fetal tissues of human, mouse, cattle, pig, sheep, cat, guinea pig, and chicken origin. Lymphocytes of tumor bearing mice and tumor patients reacted specifically in the MEM-test with antigenic components of the extracts. The cellular sensitization of the tumor-bearer was not correlated with the localization and the histologic type of the tumor. The cross-reacting oncofetal antigens obviously represent phylogenetically conserved structures.

Lymphocyte reactivity to 3-M KCl extracts from fetuses of different species of origin was shown by the macrophage electrophoretic mobility (MEMB) and/or the leukocyte migration inhibition tests in tumor-bearing mice and humans. In chemical carcinogenesis, reactivity was detectable before tumors developed. Six weeks after sc injection of 1,000 micrograms benzo[a]pyrene [(BP) CAS: 50-32-8] into XVII/Bln mice, the MEMB test became positive. The latent period was 15 weeks after 1.0 micrograms BP, indicating a dose-response relationship of the phenomenon. Painting of mouse skin with 7,12-dimethylbenz[a]anthracene [(DMBA) CAS: 57-97-6], croton oil (CAS: 8001-28-3), or benzene (CAS: 71-43-2) had the same sensitizing effect as BP. In contrast to the strong carcinogens BP and DMBA that caused lymphocyte reactivity to persist until tumors developed, benzene and the promoter croton oil induced only a transient effect. Termination of treatment abolished reactivity within 12 weeks. Lymphocyte reactivity to fetal extract in normal cell proliferation was evident from the fact that two-thirds-hepatectomized rats and BCG-treated mice became MEMB-positive. In hepatectomized rats the effect was reversible according to the completion of liver regeneration. Lymphocytes from tumor-bearing mice reacted with mouse and human fetal extract as well as with extracts from different developmental stages of frogs and fish. Fetal extracts were assumed to contain a phylogenetically conserved antigen.

Calf serum beads coated with antigen-antibody complexes were used as cellular immuno-adsorbents to separate mouse T-lymphocytes with a purity of more than 90%. The beads coated by means of glutaraldehyde could be used at least three times without loss of cell-binding capacity.

CA 125 was determined in the sera of 94 female patients afflicted with various gynecological diseases. Benign ovarian tumors and gynecologic malignancies outside the ovaries had normal CA 125 values in most cases. Patients with ovarian carcinomas in advanced stage had high levels. 6 women, who had hepatic metastases from ovarian cancer, showed a so-called prozone effect in serum titration, that means, the CA 125 concentration at first rises to reach a peak at a dilution of 1:2 to maximally 1:20, and then reveal a normal reciprocal dilution behavior. Whether hepatic metastases as a possible source of marker production are responsible for this phenomenon should be examined in future studies.