Epigenetics is defined as "the study of mitotically and/or meiotically heritable changes in gene expression that cannot be explained by changes in the DNA sequence". Setting up the epigenetic program is crucial for correct development and its stable inheritance throughout its lifespan is essential for the maintenance of the tissue- and cell-specific functions of the organism. For many years, the genetic causes of cancer have hold centre stage. However, the recent wealth of information about the molecular mechanisms which, by modulating the chromatin structure, can regulate gene expression has high-lighted the predominant role of epigenetic modifications in the initiation and progression of numerous pathologies, including cancer. The nucleosome is the major target of these epigenetic regulation mechanisms. They include a series of tightly interconnected steps which starting with the setting ("writing") of the epigenetic mark till its "reading" and interpretation will result in long-term gene regulation. The major epigenetic changes associated with tumorigenesis are aberrant DNA methylation of CpG islands located in the promoter region of tumor suppressor gene, global genomic hypomethylation and covalent modifications of histone N-terminal tails which are protruding out from the nucleosome core. In sharp contrast with genetic modifications, epigenetic modifications are highly dynamic and reversible. The characterization of specific inhibitors directed against some key epigenetic players has opened a new and promising therapeutic avenue, the epigenetic therapy, since some inhibitors are already used in clinical trials.

Because of the unavailability of effective therapies to block or reverse the progression of androgen-independent prostate cancer, it seems obvious to target growth signaling pathways for which frequently recurring mutations have been identified. Acquired mutations of the PTEN gene have been reported in several tumor types, including up to 30% - 60% of prostate cancer tumors. This results in constitutive activation of the PI3K/Akt pathway which then represents a major target to prevent dysfunctions in cell growth, survival and motility. Our experience and, therefore, our own tools allow us to design new inhibitors of growth factor receptor tyrosine kinase, PDK-1 and farnesyltransferase activities. These original compounds could selectively switch off one or several steps of the multifunctional pathway and constitute lead compounds in the design of new classes of potent drugs.

Current treatment of glioblastomas relies on surgical resection, radiotherapy and chemotherapy. However, the efficacy of these therapeutics is still limited and new therapeutic approaches based on the understanding of brain tumor biology are emerging.

Megalencephalic leukoencephalopathy with subcortical cysts is a rare disease with autosomal recessive inheritance.

Evaluation and management of renal cysts Renal cystic diseases are a heterogeneous group of conditions including heritable, developmental, and acquired disorders. They are united by the presence of microscopic or giant fluid-filled cavities and affect both children and adults. The definitive diagnosis of many of the renal cystic diseases requires clinical, radiological, pathological, and genetic analysis. A precise diagnosis is essential for prognosis, treatment, and future genetic counselling.

The multiple endocrine neoplasia (MEN) syndromes are hereditary monogenic diseases that are transmitted as autosomal dominant traits, and are characterized by the development of tumors and hyperplasias in several endocrine organs. The causative genes of the 2 principal forms of MEN have been recently identified; a protooncogene for MEN2 (the RET gene) and a tumor suppressor gene for MEN1 (the MEN1 gene). Correlations between phenotype and genotype were described in the case of RET mutations that could help in defining the screening methods and the preferable age of prophylactic thyroidectomy. No correlations were established between the mutations of the MEN1 gene and the phenotype of patients suffering from MEN1. We present here a synopsis of the recent results of the genetics of MEN syndromes underlining their clinical implications.

To define a clinical and secretory profile of paragangliomas extra-adrenal chromaffin tumors.

Neurofibromatosis 1(NF1) is one of the most common genetic diseases. NF1 is an autosomal dominant genetic disorder and half of affected individuals have NF1 as the result of a new gene NF1 mutation. The offspring of an affected individual have a 50% risk of inheriting the altered NF1 gene. The disease manifestations are extremely variable, even within a family. NF1 is characterized by multiple cafe au lait spots, axillary and inguinal freckling, multiple discrete dermal neurofibromas, and iris Lisch nodules. Learning disabilities are frequent. Less common but potentially more serious manifestations include plexiform neurofibromas, optic and other central nervous system gliomas, malignant peripheral nerve sheath tumors, vasculopathy, and osseous lesions.

The management of advanced stage ovarian cancer has been deeply modified over the last few years. In patients with massive peritoneal spread, the use of neoadjuvant chemotherapy, followed by interval surgery, reduces the morbidity of radical surgery with an improvement of the quality of life. Nevertheless, results of ongoing randomized studies should be waited before stating about the results on survival of such management compared to initial debulking surgery. Waiting such results, the standard treatment of advanced stage ovarian cancer in 2005 remains initial surgery, performed in order to obtain ideally a total resection of all macroscopic diseases, and followed by adjuvant chemotherapy. However, in patients with massive spread, interval debulking surgery is becoming an interesting option, and will perhaps become a standard management. But criteria to select patients between initial and interval debulking surgery should be clearly defined. Those different points will be studied in this paper.