Clear cell sarcoma of tendons and aponeuroses is a rare mesenchymal tumor in childhood. It is difficult to treat and its prognosis is bad.

Solitary biliary cysts and polycystic liver disease are among the most frequent cystic lesions of the liver. Solitary biliary cysts have a prevalence of 1 to 2 percent; they are almost always asymptomatic and do not require treatment. Ultrasonography shows a regular, round or oval, entirely liquid and trans-sonic image sufficient to make the diagnosis. Complications are exceptional. Polycystic liver disease is associated with polycystic kidney disease in 50 percent of the cases, and the prognosis depends on the degree of renal failure. In polycystic disease of the liver and kidney the hepatic cysts develop before the renal cysts. Complications (e.g. cyst infection) are rare and principally observed in patients with terminal renal failure. In patients with complicated polycystic liver disease various treatments, such as needle aspiration, alcohol sclerotherapy or surgery, must be considered.

Detection of subjects from a multiple endocrine neoplasia type 1 family must rest on clinical, biochemical and radiological data, since study of the genome is unable to detect these subjects. In the new family described here, 6 out of the 14 subjects explored were affected. One had a confirmed pancreatic endocrine tumour and in 3 others a pancreatic endocrine tumour was highly probable, since insulin and glucagon levels, as well as ultrasonic exploration of the pancreas were pathological. Measurements of gastrointestinal hormones gave normal results in all cases. We conclude that to detect this endocrine neoplasia in subjects at risk it seems necessary to measure plasma insulin levels and perform an abdominal ultrasonography.

Granulocytic sarcoma is more frequent in adults; it can be a tumoral localization of acute non-lymphoblastic leukemia. This report describes an infantile case revealing an acute myeloid leukemia.

The cure of human cancers at a micro- or macro-metastatic stage of the disease is restricted to chemocurable forms which represent only 10% of all leukemias, lymphomas and solid tumors. Local conditions in the tumor site and biological characteristics of tumor cells are responsible for the resistance to treatment of many malignant tumors. Gene therapy can be applied to locally incurable tumors as well as to systemically disseminated malignancies. Genic "Surgery" can be produced by local intra- or peritumoral injection of viral vectors and/or virus-producing cells. For example in the case of brain tumors the use of retroviruses which are cell-cycle dependent for the injection of target cells is expected to spare the non-cycling normal brain cells from the dividing tumor cells. Three main types of systemic gene therapy are presently under study: a) VDEPT (Virally Directed Enzyme Prodrug Therapy) attempts to induce the production of an enzyme which transforms a prodrug into a cytotoxic drug in the engineered tumor cells. b) Ecotropic genic immunotherapy (tumor-site directed immunotherapy) can be used to produce sufficient local concentrations of cytokines to induce antitumor immune response at the tumor site(s). c) Systemic antigenic gene therapy aims to induce tumor-specific antigens by transfection of tumor cells in order to initiate immune rejection of residual disease by the patient lymphocytic killer cells. The conceptual basis and the limitations of these therapeutic approaches are discussed.

Review of the therapeutic use of DNA transfer to treat a certain number of hereditary diseases (such as adenosine deaminase deficiency) or acquired diseases. The strategies (ex vivo manipulation or direct in vivo transfer of the corrective gene), vectors (retrovirus, adenovirus, nonviral vectors), and diseases which can benefit from gene therapy are considered and discussed together with an evaluation of the risk of gene therapy.

Familial breast cancers represent about 10% of all cases of breast cancers. A predisposition locus has been located in the 17q21 chromosomal region. Nineteen French breast and breast-ovarian cancer families were tested for linkage with five highly polymorphic 17q markers. The five breast-ovarian cancer families as a group give positive evidence for linkage, whereas the 14 breast cancer families do not. Heterogeneity of linkage of familial breast cancer is significant in France and supports the existence of more than one susceptibility gene.

The treatment of kidney cancers raise difficult problems. Usual treatments combining surgery, radiation therapy, chemotherapy and hormonotherapy are poorly effective. The immunotherapy gave only an objective response rate of 25% in metastatic renal cell carcinomas. Among cellular resistance mechanisms of renal carcinoma, the multi-drug resistance (MDR) phenotype and the glutathione redox cycle have been studied. The MDR is related to overexpression of a 170 kDa membrane glycoprotein, the so-called P glycoprotein (Pgp). This protein is a pump able to extrude from cytoplasm drugs with various structures and mechanisms. The Pgp is encoded by the MDR1 gene expression is very low in most of the normal tissues, except in colon, liver and kidney. In these tissues, the Pgp would ensure a detoxifying function related to cellular toxic compounds, elimination or transfer of molecules synthesized by the cells. According to the intrinsic resistance of renal carcinoma, MDR1 gene expression has been determined. Approximately, 80% of fresh kidney cancer before chemotherapy express resistance phenotype. Reversal compounds specifically inhibiting Pgp were found, such as verapamil, cyclosporin or quinidine. Unfortunately, the two first compounds give cardiac toxicity and immunosuppression, respectively. So far, clinical trials have not been demonstrating, but no biological resistance measures were determined, in parallel. According to the multifactorial resistance the association of reversals to chemotherapy should be introduced in clinical trials, in correlating clinical response to biological mechanisms of resistance.

The CD44 group of transmembrane glycoproteins encompasses several isoforms expressed in a variety of tissues. All isoforms are encoded by the same gene on chromosome 11 and are formed by alternative splicing of their mRNA. CD44 isoforms belong to the family of cell adhesion molecules and to the sub-family of the hyaladherins in consideration of their affinity for hyaluronate and their structural homology with the cartilage link protein. The standard form of CD44, CD44H exhibits a high affinity for hyaluronate, plays a role in the uptake and degradation of this glycosaminoglycan and participates in cell locomotion in its presence. In physiology, CD44H plays a role in the homing of lymphocytes into Peyer's patches, in organogenesis and in the degradation of hyaluronate in lung or lymphoid tissue. In pathology, CD44H probably enhances the tumorigenic properties of some lymphomas and melanomas. The variant form CD44E exhibits low affinity for hyaluronate and its role in cell-cell adhesion in epithelia is suspected. The variant form CD44V (or CD44M) confers metastatic properties to rat carcinoma cells and is expressed in human breast and colorectal cancer and in adenomatous polyps.

Follicular lymphomas are a subgroup of non-Hodgkin's lymphomas with a low-grade malignancy. They are characterized by a frequent chromosome abnormality, a translocation between chromosome 14 and chromosome 18. This translocation plays a role in the development of this disease. The course of follicular lymphomas is slow, usually lasting several years but is ultimately fatal, Their treatment is controversial. Recently, an association of chemotherapy and alpha interferon appeared promising. Other drugs such as fludarabine or 2' chlorodeoxyadenosine are currently tested.

Jun and Fos are major components of the transcriptional complex AP-1 (Activator Protein-1), a collection of dimeric transcriptional activators composed of members of the Jun and Fos family of bZIP proteins, that bind to a common site known as TRE (TPA Responsive Element) or the AP-1 site. Transcription of c-jun is rapidly induced by exposure to different extra-cellular signals like growth factors, cytokines, tumor promoters (TPA), UV and other DNA-damaging agents. Transcriptional activation of c-jun is a two step mechanism. First, the pre-existing c-Jun protein is activated by posttranscriptional modifications, and second, modified c-Jun activates its own transcription, and the expression of AP-1-dependent genes. Modifications of c-Jun include dephosphorylations, phosphorylations and oxydo-reduction. The transcriptional activation by c-Jun is modulated by heterodimerization with other members of the bZIP family of proteins, and by transcriptional interference with other transcription factors like some members of the hormone nuclear receptors, or MyoD. AP-1 is tightly associated to both the control of cell proliferation and the oncogenic process. Constitutive activation of AP-1 leads to cell transformation in vitro, probably due to the accumulation of homodimeric c-Jun:c-Jun complexes. This hypothesis has been directly confirmed by constructing c-Jun hybrid proteins capable to form only homodimers. Deregulated expression of such proteins efficiently transforms primary cells in culture. These hybrid proteins constitute a powerful tool in order to identify new cellular functions AP-1-dependent, involved in the control of cell proliferation.

The establishment of a cell culture system for the clonal development of hemopoietic cells made it possible to discover the proteins that regulate cell viability, growth and differentiation of different hemopoietic cell lineages and the molecular basis of normal and abnormal development in blood-forming tissues. These regulators include cytokines now called colony stimulating factors (CSFs) and interleukins (ILs). Different cytokines can induce cell viability, multiplication and differentiation, and hemopoiesis is controlled by a network of cytokine interactions. This multigene network includes positive regulators such as CSFs and ILs and negative regulators such as transforming growth factor beta and tumor necrosis factor. The cytokine network which has arisen during evolution allows considerable flexibility depending on which part of the network is activated and the ready amplification of response to a particular stimulus. The CSFs and ILs induce cell viability by inhibiting programmed cell death (apoptosis). Programmed cell death is also regulated by the genes wild-type and mutant p53, c-myc and bcl-2, and suppression or induction of this program can result in tumor promotion or tumor suppression. Cytokines that regulate normal hemopoiesis can control the abnormal growth of certain types of leukemic cells and suppress malignancy by inducing differentiation. Genetic abnormalities that give rise to malignancy in these leukemic cells can be by-passed and their effects nullified by inducing differentiation and programmed cell death. The hemopoietic cytokines discovered in culture are active in vivo and are being used clinically to correct defects in hemopoiesis.

The nm23-H1 gene encoding the nucleoside diphosphate (NDP) kinase A has been proposed as a tumor metastasis suppressor. Two important features emerge from published data: 1) an inverse correlation between the metastatic invasion and the level of NDP kinase/Nm23 was observed in melanomas, hepatocellular carcinomas and, in some studies, on breast carcinomas; 2) an overexpression of NDP kinase/Nm23 was observed in several solid tumors as compared to normal surrounding tissues, positively correlated with aggressiveness in the case of neuroblastomas. The level of NDP kinase/Nm23 in tumors appears to be altered in different ways, related or not to the metastatic potential, depending on the tissue of origin. Its evaluation as a prognostic or diagnostic marker of tumor invasion and aggressiveness deserves further study.

The tumor suppressor genes presently individualized are still few. A step in their identification is the search for chromosomal deletions and loss of heterozygosity. These studies are summarized.