Nectin and nectin-like (necl) proteins form a family of 9 adhesion molecules that belong to the immunoglobulin superfamily. They play a key role in different biological processes such as cell polarity, proliferation, differentiation and migration in epithelial, endothelial, immune and nervous systems. Besides their role in physiology, they have been involved in different pathological processes in humans. They serve as virus receptors (poliovirus and herpes simplex virus), they are involved in orofacial malformation (CLPED1) and recently they have been described as markers, actors and potential therapeutics targets in cancer. Among them, necl-5, nectin-2 and nectin-4 are overexpressed in tumors, and are associated with a poor prognosis. On the opposite, necl-1, necl-2 and necl-4 act as tumor suppressors and are repressed in cancer. The involvement of nectins and necls molecules in cancer and their potential used in therapy is discussed in this review.

Asymmetric cell division is the process by which a single cell gives rise to two different daughter cells. This process is important to generate cell diversity during the development of multicellular organisms, as well as for stem cell self-renewal in adults. Current knowledge on so-called cancer stem cells suggests that a loss of asymmetry during their division could lead to overproliferation and favour tumorigenesis, highlighting the importance of deciphering the mechanisms governing asymmetric cell division. Two mechanisms can lead to an asymmetric cell division: asymmetry can either be governed by proximity to a given cellular environment (or niche), in which case the mechanism is referred to as extrinsic, or the mother cell polarizes itself without external intervention, in which case the mechanism is referred to as intrinsic. In the last 20 years, our understanding of intrinsic mechanisms leading to asymmetric cell division has progressed, largely after studies carried out in model organisms such as the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. These models allowed the identification of molecular complexes used by nearly all the cells that divide asymmetrically, including human cells. Here we review the main intrinsic mechanisms of asymmetric cell division as described in model organisms and discuss their relevance towards mammalian tumorigenesis.

Plexiform neurofibromas of the orbit, sometimes extending to the temporal region and the face, are considered to be a rare but devastating and disfiguring complication of neurofibromatosis type 1. The first symptoms appear in infancy and the involvement of the orbit and the face is present in nearly all children after the age of 5. The disease is unilateral in most cases but can exceptionally involve both sides of the face. Progressive deformation of the orbital frame due to the expanding plexiform neurofibroma and buphthalmos occurs in a large proportion of cases. The associated sphenoidal dysplasia, which is thought to be, according to the most recent hypothesis, genetically determined, will inescapably increase the burden to the orbital content, cause pulsating proptosis and will endanger noble structures, finally resulting in loss of vision. Using the Jackson classification, the authors report their personal series of 22 cases (19 operated). Until now, there has been no effective medical treatment for plexiform neurofibroma and surgery remains the standard care for these patients. Controversies remain about the timing of the first operation and today most multidisciplinary teams involving plastic, maxillofacial, ophthalmologic, and neurosurgeons favor early intervention to try to minimize the secondary deformation of the orbital and facial skeleton. A number of cases of plexiform neurofibromas are illustrated within the three Jackson groups and treatment results of the rare elephantiasis neuromatosa cases are presented. Special techniques such as preoperative embolization of heavily vascularized plexiform neurofibroma are also discussed.

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal-dominantly inherited genodermatosis that predisposes to the development of benign hair follicle tumours, lung cysts, kidney tumours, and possibly colonic cancers, due to mutations in the FLCN gene. We report cases involving a new mutation in three unrelated families.

Prognostic factors able to predict lymphoma patient's outcome are necessary to inform the patient and to choose the appropriate treatment. Beside the essential documentation of the pathological lymphoma subtype, several factors (such as age, performance status, Ann Arbor disease stage, LDH level...) easy to assess are used and help to establish prognostic indexes for each lymphoma entity. Numerous biomarkers obtained on fresh or frozen tissue using molecular techniques are currently described and may help to optimize the clinical care of lymphoma patients tomorrow.

Basal-like carcinomas represent 10 to 15% of invasive breast carcinomas and have been identified from gene expression studies. Morphologically, these tumors are undifferentiated histopronostic grade 3 carcinomas, identified in clinical practice according to their immunophenotype "triple zero" (estrogen, progesterone and ERBB2 negative) associated with the high molecular weight cytokeratins 5/6/14 and/or EGFR expression. At the molecular level, these tumors harbour nearly 100% P53 mutations, a high rate of PTEN mutations with an AKT pathway's activation and numerous chromosomal alterations such as gains and losses. They share a high degree of similarity at the morphological, phenotypical and molecular level with BRCA1 tumors that justify the proposal of a different name such as "triple zero/BRCA1 like" carcinomas for sporadic basal-like carcinomas. Indeed, the current "basal-like" name could suggest a myoepithelial cellular origin of such lesions. Furthermore, tumors with such a basal-like immunophenotype constitute a heterogeneous group of tumors encompassing good prognosis tumors such as adenoid cystic and juvenile secretory carcinomas. There is an urgent need for more specific therapies for basal-like/triple zero/BRCA1-like tumors. Therapeutic progresses rely on a better understanding of the molecular alterations that occur in these tumors and the BRCA1 tumors. Indeed, recent clinical trials with PARP inhibitors for basal-like/BRCA1 like tumors should improve the prognosis of these patients and are a direct benefit of a better understanding of the molecular biology of these tumors.

Somatic mutation theory explains how DNA damage can lead to the malignant transformation of cells. It therefore elucidates the connection between genotoxic agents and cancers. Mutational spectra, which tend to be characteristic of a cancer type, are available for certain genes like p53 which is frequently mutated in tumors. A mutational spectrum could therefore be the signature of the genotoxic agent(s) at the origin of the malignant transformation. Ligation-mediated PCR (LMPCR) is a genomic sequencing method that can be used for the mapping of DNA damage at nucleotide resolution. Such a mapping can then be compared to a mutational spectrum to test the hypothesis that implies one agent can cause mutations into one cancer type. LMPCR has been used this way to map DNA damage generated by different UV wavelengths. The frequently damaged sites following UVB irradiation correlate with the mutational spectrum of p53 in skin cancer. Similarly, BPDE, the activated form of the benzo[a]pyrene present in tobacco smoke, generates frequent adducts at sites corresponding to mutation hotspots of p53 in lung cancers. Still, the correlation between BPDE damage sites and p53 mutations is not perfect and this suggests a role of other genotoxic substances that are also present in tobacco smoke, such as the nitrosamine NNK. Finally, and beyond this objective of better understanding somatic mutagenesis, LMPCR is commonly used whenever DNA damage frequency and/or repair is to be investigated.

The aim of this study is to evaluate the implication of BRCA1 gene and the mitochondrial micro satellite (situated between 303 and 315 positions) mutations in the occurrence of breast cancer in Tunisia.

High risk may be defined as either an absolute risk greater than 20 % or a relative risk greater than 4. Concerning breast and ovarian cancer, high risk patients include carriers of a constitutive deleterious mutation of BRCA1 or BRCA2 genes, patients with a significant family history of breast or ovarian cancer, and patients who have been diagnosed a benign breast lesion with a high risk of degeneration, i.e. atypical hyperplasia. Following up such patients relies on specific strategies. A center including a large panel of physicians involved in the various modalities for patients' management (geneticians, radiologists, gynecologists, plastic surgeons, pathologists, endocrinologists, psychologists, medical oncologists) has been created at Tenon Hospital with this purpose. The collaboration of these different specialists with the referent physician of the patient allows for the definition and the implementation of a patient-centered follow-up continuously updated to take into account the different periods of a woman's life, according to best practices recommendations and the evolving state-of-the art.

Tamoxifen is a prodrug mainly metabolized by the CY2D6 cytochrome. More than 80 variants of the CYP2D6 gene have been identified. They predict four different enzymatic phenotypes: ultra-rapid metabolizers (UM), extensive metabolizers (EM), intermediate metabolizers (IM) and poor metabolizers (PM). Six retrospectives studies suggest a link between some polymorphisms of the CYP2D6 and tamoxifen efficacy and two studies have found no statistically significant data. Today, level of proof remains insufficient to recommend the testing of a patient's genotype before tamoxifen prescription. Designing prospective studies is necessary before considering therapy strategies based on pharmacogenetics data. In pre-menopausal breast cancer PM or IM patients, an increase in dosage of tamoxifen or a treatment with LH-RH analogues with aromatase inhibitors (AI) may be beneficial instead of the actual recommendations of a 5-year tamoxifen therapy. In postmenopausal EM patients, tamoxifen may be as efficient as AI. In post-menopausal PM patients, a switch strategy may be inferior to a 5-year IA strategy, which would therefore be the standard of care.

Upper urinary tract urothelial cell carcinomas (UUT UCC) are rare sporadic tumors. Recent epidemiologic and molecular data have shown a singular susceptibility of UUT UCCs for specific risk factors. The main exogenic factors involved in UUT UCCs carcinogenesis remain tobacco and occupational exposure (aromatic amines, polycyclic hydrocarbures and chlored solvents). Enzymatic variants of detoxification system may be responsible of carcinogenesis with these toxics. Tumors induced by phenacetine consumption are decreasing since it was banned in the 1970s. Also, acid aristolochic exposure (Balkan nephropathy, Chinese Herb nephropathy) has been demonstrated to specifically induce UUT UCCs. Familial genic polymorphism of detoxification system would explain geographic distribution in endemic areas. In Taiwan, chronic arsenic exposition would constitute the main risk factor of UUT UCC. However, theses mechanisms of carcinogenesis remain unclear. The knowledge of UUT UCC development mechanisms implying toxic detoxification systems is still incomplete. To date, there is a growing body of evidence supporting that the interaction between individual genetic susceptibilities and environmental toxic exposure is a key to explain carcinogenesis in the majority of sporadic UUT UCC occurrence.

To review main knowledge about lobular intra-epithelial neoplasia with special interest for daily practice management.

Fundamental research in Dermatology has been once more very active during the past year and more specifically focused on immunological grounds of inflammatory diseases, the identification of risk loci associated with psoriasis and tumors, cutaneous lymphomas and on the genodermatosis where large international collaborative studies provided with a molecular understanding of an increasing amount of conditions especially affecting pigmentation and differentiation. In silico investigations become increasingly prominent especially with the rising power of new actor, China, the demographical and resulting epidemiological weight of which can hardly be challenged. Some of these fundamental breakthroughs might result in practical interventions although in an undefined future.

Approximately 10% of patients diagnosed with breast cancer will develop cancer in the contralateral breast within 10 years. The risk factors for bilateralization are now better understood thanks to advances in molecular biology. Based on reports in the literature the main risk factors are presence of brca 1 or 2 gene mutations and family history. Despite the increasing incidence of breast cancer, this special aspect of the disease remains poorly studied in Gabon as well as in Black Africa in general. Incidence is increasing. This report describes 5 patients and discusses their profiles in relation to the literature. This study provides on update on current knowledge.

Small-cell lung cancers (SCLC) are aggressive malignancies, however, characterized by high primary chemosensitivity. Unfortunately, for the vast majority of patients, relapse is the rule with emergence of secondary resistance mechanisms. In the era of molecular targeted therapies, characterization of a number of molecular abnormalities has encouraged implementation of several clinical trials. This literature review summarizes the various pharmacological approaches used in SCLC to improve survival in localized and extensive forms of the disease. Initial trials with molecular targeted therapies have not been able to improve clinical outcome compared to the standard etoposide-cisplatin chemotherapy regimen in extensive forms. However, new targets continue to be identified and many treatments are currently being assessed, including blockade of angiogenesis, signal transduction, cell cycle or induction of apoptosis.