It is now evident that development of hepatocellular carcinoma (HCC) in human is associated with a long series of cellular and tissue changes that precede the ultimate development of the cancer. During recent years, enormous progress in molecular research on HCC has been made, particularly in the area of integration of HBV DNA to host cell and oncogene association with carcinogenicity. A high ratio of HCCs from patients in endemic area has integrated HBV DNA in cellular DNA and in some cases, chromosomal translocations associated with HBV integration were observed, suggesting that the integration or the results thereof are connected with cancer development. Employing a DNA-mediated transfection assay using NIH3T3 mouse fibroblasts with high molecular weight DNA, we detected three cellular transforming genes (lca, N-ras, hst) in primary human HCC. However, little is known as to the linkage between the activation of these genes and liver carcinogenesis. In most human primary HCC tissues, at least two oncogenes, c-myc and N-ras are overexpressed, while in some cases other oncogenes c-fos or lca are overexpressed. It is likely that multiple c-oncogens are important in HCC, but specific transcripts for the malignancy of HCC were not detected. At present, we could not find any relationship between the expression of c-oncogenes and integration of HBV, serological markers or the degree of differentiation. Of the experimental animals most frequently used for studies of liver cancer, the rat is best understood and mimics closely many of the lesions in humans. It is of interest to consider that the identification and elucidation of the mechanisms underlying carcinogenic processes in the rat may offer testable hypotheses for steps in the human.

To investigate the effect of interferon-gamma (IFN-gamma) on the immunotherapy, we used the autocrinically stimulated system in which a mouse IFN-gamma cDNA was transferred by infection with a chimeric retrovirus containing the IFN-gamma gene. First, we established a tumor specific CTL clone (E-4) against 203-glioma cells (a 20-methylcholanthrene induced mouse ependymoblastoma line of C57BL/6 mouse origin), and then transferred murine IFN-gamma cDNA into E-4 by using retroviral vector (pSVX(Mu gamma delta A]. Out of five gene-transferred subclones, E gamma-4, E gamma-5, E gamma-6, E gamma-7 and E gamma-9, two subclones (E gamma-6 and E gamma-9) constitutively produced 8- to 10-fold amounts of IFN-gamma as compared with the parental E-4. Moreover, these two subclones exhibited two to three times higher killing activity against 203-glioma than the parental cells. The enhancement of the killing activities was abrogated by an adequate addition of anti-IFN-gamma antibody. No alteration was seen after the gene transfer in cell surface phenotypes, Thy-1+, Lyt-1-, Lyt-2+3+ and asialo-GM1-. Fluorescence-activated cell sorter (FACS) analysis showed that the surface expression of major histocompatibility complex (MHC) Class I antigen, H-2Kb, of parental E-4 was augmented remarkably, and it was not altered by the IFN-gamma gene transfer, but the Class II antigen, I-Ab, was slightly enhanced on the two IFN-gamma-producing sublines. Since it is considered that in the vicinity of the constitutively IFN-gamma-producing CTL cells, tumor cells are exposed to a high concentration of IFN-gamma and may be stimulated to induce or enhance the expression of surface antigens including MHC antigens as well as tumor associated antigens in relation to immune recognition. The 203-glioma cells pretreated with IFN-gamma were more efficiently killed by both the parental E-4 and the gene-transferred sublines. It was thus suggested that the specific tumor killing activity of the gene-transferred CTLs was augmented by the constitutive production of IFN-gamma derived from the exogenous gene. As the next step, a mouse IFN-gamma cDNA was transferred into a neuroblastoma line C1300 of A/JAx mouse origin. Two infected subclones C gamma 3 and C gamma 22, were obtained as a low and a high producers, respectively. Both IFN-gamma gene transferred cells remained unchanged as regards in vitro cell growth, morphological appearance and differentiation antigen expression such as neurofilaments after the IFN-gamma gene transfer. On the other hand, expression of MHC Class I antigens of both subcloned lines was extremely augmented at the surface expression level as well as at the transcription level, re

In April, 1985, a 60-year-old Japanese male was diagnosed as having refractory anemia with an excess of blasts (RAEB). He thus was treated solely with blood transfusions until June, 1986, when a new diagnosis revealed that his illness had been transformed into acute myelogenous leukemia (M2). Chromosome analysis at the initial diagnosis had revealed a normal male karyotype. When the subsequent diagnosis of AML was made, however, a chromosomal abnormality [46, XY, -20, +der (20) t (?8;20) (q22;p13)] was detected. Myelodysplastic syndrome (MDS) in patients evidencing a karyotypic alteration from the initial karyotypic findings progresses in severity that includes overt leukemia, and results in a shorter survival than in patients who show no further karyotypic changes. Therefore, the prognosis of patients with MDS can be predicted more accurately by subsequently reanalyzing their chromosomes after the initial analysis, as well as by examining their peripheral blood/counts, and by monitoring bone marrow cytology.

Great progress has been made in clinical research on non-Hodgkin's lymphoma during the last 15 years. Surface marker and DNA analyses of immunoglobulin and T-cell receptor genes are essential for new classification of the disease according to the cellular origin of tumor cells. This approach resulted in the establishment of new disease entities such as adult T-cell leukemia/lymphoma(ATL), immunoblastic lymphoadenopathy (IBL)-like T-cell lymphoma, and the pleural B-lymphoma occurring in long-standing pyothorax. New retrovirus, HTLV-I, was found during studies on ATL. Prevention of HTLV-I infection is an important project. HTLV-I negative ATL was also found and is of particular interest in understanding leukemogenesis of ATL. An oncogen such as bcl-2 is important for characterization of follicular lymphoma. Prognostic factors of patients with T-lymphoma are completely different from those of B-lymphoma. Risk grouping by combination of major prognostic factors is useful for the selection of the best treatment modality and the accurate estimation of prognosis of patients at initial presentation. The effect of combination chemotherapy should be evaluated separately between T- and B-lymphomas because of the difference in response rate and prognostic factors.

Recently it has been suggested that proto-oncogene plays a role not only in cellular proliferation, development and differentiation, but also in neoplastic transformation. We now show the expression and its localization of c-myc, c-fms and c-sis proto-oncogenes in human developing chorionic tissue and fresh surgical specimens of mole and choriocarcinoma with the method of Northern blotting and In-situ hybridization. The 2.4kb c-myc transcript has been localized to the cytotrophoblast in early placenta and also localized to the C and S typed trophoblastic cells in mole and choriocarcinoma. The 4.0kb c-fms transcript has been localized to the syncytiotrophoblast, especially the highly differentiated syncytiotrophoblast in the second and third trimesters and S typed trophoblastic cells in mole and choriocarcinoma. Moreover, the 4.0kb c-sis transcript has been localized to the cytotrophoblast in early placenta, but not detected in mole or choriocarcinoma. First, these results suggest that the stage and site specific expression of c-myc, c-fms and c-sis proto-oncogenes are clearly related to the proliferation, development and differentiation of normal trophoblastic cells. Second, the expression of c-myc, c-fms proto-oncogenes may be of particular importance in the tumorigenesis and progression of trophoblastic disease.

DNAs from 15 samples of primary stomach cancer were transfected into NIH3T3 cells. Five stomach cancer DNAs (ST1, ST3, ST6, ST7, and ST15) showed transforming activity. These transformations were caused by human cancer DNAs since human Alu repetitive sequences were detected in transformant DNAs. DNAs from transformants were screened with 22 oncogene probes available, including Ha-ras, Ki-ras, and N-ras. However, these probes did not hybridize with any human DNA in transformants. A transforming gene was cloned from an ST6-derived transformant, which turned out to be hst oncogene. By use of a probe derived from the cloned hst gene, it was shown that additional two transformants (ST7- and ST15-derived) also harboured human hst. Here I report molecular cloning of another transforming gene from an ST1-derived transformant. The transforming gene was cloned by cosmid rescue method being tagged with pSV2-gpt. The normal counterpart of the transforming gene was also cloned from a genomic phage library of human placenta DNA. Surprisingly, the transforming gene was not colinear with the placenta DNA, but was generated by the recombination of two separate genes. Comparison of the restriction maps of these genes with those of reported oncogenes showed that 3'-half of the cloned transforming gene was colinear with the 3'-half of the ret oncogene, which encodes tyrosine kinase domain. It was suggested that this gene was activated by DNA rearrangement upon transfection, placing a transcriptionally active promoter on upstream of the kinase domain. Among 4 primary transformants derived from ST1 two did not have human ret oncogene, indicating that other transforming genes were involved in these transformation events.