In experimental models chemotherapeutic agents enhance spontaneous metastases. Vascular toxicity and myelotoxicity may account for this phenomenon. However, drugs may act directly on tumor cells. Clonogenic resistant cells are involved in the metastatic process facilitation. Fundamental biological mechanisms are evoked to explain these observations. Mutagenicity and its consequences on gene expression or regulation are another hypothesis. Clinical investigations are necessary to confirm the results obtained from animal models.

Two forms of neurofibromatosis are currently described. Von Reckinghausen Neurofibromatosis (NF 1) is the classic and common form, recently localised to chromosome 17. Neurofibromatosis type 2 (NF 2) or bilateral acoustic Neurofibromatosis, formerly the "central form" of von Reckinghausen disease, is characterized by multiple brain tumors, most often bilateral acoustic neuromas. The NF 2 mutation lies on the long arm of chromosome 22. The two forms predispose to benign or malignant familial tumors, derived from neural crest germ lines, such as Schwann cells. Rapid progress in the understanding of mechanisms underlying neurological tumor formation is expected in these inherited diseases. Molecular biology will allow the precise identification of genes responsible for the neurofibromatose syndromes. Practical applications, such as screening of individuals at risk for the disease will soon be available. Medical follow-up and genetic counselling should improve as a result of these advances.

We have investigated the liver-specific expression of IGFBP-1 gene, an Insulin-like Growth Factor binding protein. Northern blot as well as transient transfection experiments, both carried out in differentiated (H4II, C2Rev7) and dedifferentiated (H5, C2) hépatoma cell lines, yielded clear cut data allowing the involvement of HNF1, a liver-specific trans acting factor, in basal IGFBP-1 liver-specific expression.

Activation of cellular proto-oncogenes can be detected in several human cancers. In the current study, alterations of C-erb B2 gene in primary human breast cancers were investigated. It was found to be amplified from 2 to 30 fold in 25% of the tumors. Correlations of gene amplification with several disease parameters was evaluated.

The identification of the viral oncogene v-erbA carried by an avian leukemia retrovirus has directly demonstrated the involvement of hormone receptors in neoplastic transformation. v-erbA represents an altered form of a nuclear receptor of the thyroid hormone T3. It blocks the differentiation of chicken erythrocyte progenitor cells and contributes to sarcoma transformation in association with other oncogenes. The protein encoded by v-erbA behaves as an antagonist against the normal T3 receptors and retinoic acid receptors. The primary effects of the protein result in altering the transcription of genes normally under control of the intact receptors. Presumably among these target genes are to be found genes which control cell differentiation and proliferation.

Acute promyelotic leukemia is characterized by a t(15;17) chromosomal translocation which results in fusion products between PML (chromosome 15) and RAR-alpha (chromosome 17). We describe 2 classes of patients which possess different PMLRAR and RARPML fusion transcripts. We then discuss the functional properties of PML and show that PMLRAR can interfere with both PML and RAR-alpha functions.

Cervical localizations of extra-adrenal paragangliomas are infrequently malignant, especially in their familial forms. An immunohistochemical study was performed on 6 cervical paragangliomas which were detected in 3 sisters at the age of 20 20. One had a lymph node metastasis. This study confirmed the diagnosis of paraganglioma with endocrine chief cells and supratentacular cells. It also enabled the hormonal contents of these cervical paraganglioma to be determined. In addition to catecholamine, these tumors may (like pheochromocytomas) produce serotonin and one or more other peptides.

Ledderhose's syndrome, or plantar fibromatosis, is a rare fibrous dystrophy and the plantar equivalent of Dupuytren's disease. It occurs mainly in adult subjects, as a plantar fibrous nodule. The authors report 7 operated cases of Ledderhose's syndrome, including one in a 14-year-old adolescent. When the plantar nodule becomes symptomatic, surgery is the only means of treatment. Plantar aponeurotomy must then be as extensive as possible to prevent recurrent.

The authors report the case of a 41-year old man who presented simultaneously with phaeochromocytoma, paraganglioma and renal carcinoma. The postoperative finding of metaiodobenzylguanidine uptake foci showed that the phaeochromocytoma was malignant. The patient's son had a phaeochromocytoma and a pancreatic cyst. The phaeochromocytoma had no clinical manifestations and had been discovered by systematic assays of urinary catecholamines and their derivatives. These abnormalities are those of Von Hippel-Lindau disease.