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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.

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.

An epidemiological study of neuroblastoma in the Rhône-Alpes area was carried out over a 5 year period. The aim was to set up a background for a screening program in order to increase the number of neuroblastoma diagnosed in children before age 1, and decrease or eliminate advanced stage neuroblastomas.