ras oncogenes are cellular genes altered by point mutation in 10 to 30% of human tumors. Under this mutated form they play a role in the malignant process, probably in association with other oncogenes. The different ras genes identified in human cancers, the point mutations that activate the ras genes and the properties of the ras proteins are described.

Three nephroblastomas, including one bilateral tumour, have been detected in three children belonging to the same family and born from a consanguinous marriage. The clinical and diagnostic particularities compared to non familial "sporadic" nephroblastomas are studied. The pathogenesis with the incidence of chromosomal anomalies, the diagnosis and the frequency of bilateral diseases along with the associated deformities and a non invasive therapeutic attitude are discussed.

Thymic lymphomas were induced in rats either with the cell culture-propagated radiation leukemia virus complex, RadLV/VL3, or with a molecularly cloned isolate, RadLV/VL3 (T + L +). Four of thirty lymphomas, that were examined for rearrangements of the c-myc domain, displayed alterations in the vicinity of the c-myc gene, compatible with the idea of proviral integration. One of the tumours was investigated further, and was shown to contain a full length-proviral insert upstream of c-myc. Eight of nine lymphomas, that were investigated with respect to RNA expression, contained a novel polyadenylated RNA which could be detected with a molecular probe derived from the U5 portion of the retroviral long terminal repeat, but not with probes derived from the U3 portion or from the whole retroviral genome. These findings suggest that a RadLV/VL3 (T + L +) provirus can induce or activate RNA synthesis from c-myc by an enhancer mechanism, and from another cellular gene by a promotion mechanism.

Four patients from two different families presented with multiple papular trichoepitheliomas of the face associated with cylindromas of the scalp and, in one of them, milium. This association, first described by Adamson, has now become classical. It is transmitted as an autosomal dominant trait with variable penetrance. Histochemical studies gave the following results: ATPase negative in the two types of tumour, phosphorylase weakly positive, NADH diaphorase positive in the basal cells of the trichoepitheliomas and diffusely in cylindromas. These results suggest that the cylindromas are of apocrine origin. Using monoclonal antibodies, it has been possible to demonstrate the presence of Langerhans cells in both trichoepitheliomas and cylindromas. The BL9 and KL3 antikeratinocyte monoclonal antibodies were negative, whereas the KL3 antibody, which recognizes the 55-57 Kd polypeptides of keratin, marked the suprabasal part of the tumours. These results are in favour of incomplete cell differentiation. Treatment with retinoids was ineffective, as in all other cases reported. Electrocoagulation or surgical excision om request for cosmetic reasons seem to be only possible treatments.

In the previous study, it was shown that the treatment of human neuroblastoma cells with human interferon-gamma (HuIFN-gamma) induced the morphological changes. However, the treatment with human interferon-alpha (HuIFN-alpha) or -beta (HuIFN-beta) did not induce them. In the present study, the effect of HuIFNs on the overexpression of N-myc of the human neuroblastoma cells (GOTO strain) is examined. The treatment of GOTO cells with rHuIFN-gamma inhibits the overexpression of N-myc, and its degree is dependent on the duration of the treatment. However, HuIFN-alpha and HuIFN-beta did not inhibit the overexpression of N-myc. This suggests that the oncogene N-myc may have relation to the morphological differentiation of human neuroblastoma cells because only the HuIFN-gamma, which induces the morphological differentiation, inhibits the overexpression of N-myc.

The ploidy of the thymus was studied in C57B1/Ka mice irradiated with 4 weekly X-Ray doses of 1.75 Gy. The determination of nuclear DNA content was performed by flow cytometry of intact thymocytes labeled with propidium iodide in presence of a mixture of chicken and rainbow trout red blood cells as internal reference standards. The method has been tested by detecting the sex difference in DNA content of G0/G1 of normal thymic mouse cells. The mean value was 2.9% higher in female mice. The thymus of almost 60% of irradiated male mice present a slight hypoploidy of 2.6% one month after the last irradiation.

Four cases of bilateral nephroblastoma out of a total number of 99 cases have been observed during a period of 18 years at the INSE of Tunis (4%). The frequency of associated anomalies, the familial incidence, the young age of the patients are underlined. The main therapeutic modalities are discussed. Based on the most recent studies published in the literature, the prognosis of bilateral nephroblastoma has been improved in recent years with a possibility of survival at 2 years exceeding two thirds of the cases.

From 41 reviewed cases and 2 personal observations of the WAGR syndrome, the main symptoms and their relative frequency are described: aniridia, mental retardation, Wilms' tumor. Sexual anomalies and gonadoblastoma are less frequent. The chromosomic micro-deletion can be shown by using highly sophisticated cytogenetic techniques, or suspected by blood enzymatic dosage (mainly catalase). Kidney echographic follow-up is highly recommended.

The authors describe a family in which the mother and one son are affected by oesophageal leiomyomatosis and nephritis with haematuria. The mother also presents hypertrophy of vulva and clitoris, and her son has perceptive deafness and congenital cataract. In the medical literature only 15 cases of oesophageal leiomyomatosis in children and adolescents could be found. The association with Alport's syndrome was first described by Torres and Guarner in 1983.

The authors have studied the different situations that prompt a request for genetic counseling if different members of the same family suffer from cancer. Six possibilities are considered: the cancer concerned is a genetic disease per se (e.g. retinoblastoma, thyroid cancer with amyloid stroma); the genetic disease is often complicated with cancer (e.g. intestinal polyposis); the genetic disease is occasionally complicated with cancer (e.g. neurofibromatosis); cancer is part and parcel of the genetic disease (e.g. chromosomal abnormalities); in addition, there are two special situations: "cancer-prone families" and families who request genetic counseling after one single case (e.g. cancer of leukaemia in a child).