Focus on mesothelioma and the mesothelial cell.

Diffuse malignant mesothelioma (DMM) is a tumour which arises from cells of mesodermal origin layering the surface of the thoracic and abdominal serosal cavities of the body. All epidemiological studies indicate that its incidence is increasing in males in industrialized countries, obviously in direct relation with past occupational exposure to asbestos [1-3]. However, it is now well demonstrated that other mineral fibres may induce DMM [4], and in addition, some synthetic fibres in small rodent'> [5). Although past occupational exposure to asbestos is presently the main causal factor of DMM in man, it remains that no exposure is found in about 1/3 of cases, as illustrated by the case-control study presently carried out in France. Two major problems are associated with DMM. First a difficult diagnosis [6). In fine, the defmite diagnosis of DMM is based on histological examination, by trained pathologists, using immunohistochemichal stainings [7]. Second, a poor prognosis since all classical treatments, surgery, radiotherapy as well as chemotherapy, have demonstrated their ineffectiveness in DMM. Because of these different issues, many studies have been performed throughout the world to help improve the knowledge on DMM but no scientific event had given the opportunity for clinicians and scientists to gather together to discuss the past and new data on DMM. Indeed, up to now, the problems related to DMM were mainly considered during workshops related to asbestos effects. It was thus decided to organize a conference focusing on aiJ aspects of the biology of DMM. This was held in Paris between September 30-0ctober 2, 1991; it gave the opportunity for several teams involved in research on mesothelial cells and mesothelioma to meet. The proceedings of the conference appear as issue No. 11 of the European Respiratory Review [8), where the reader will find the summary of the past data and recent information concerning the histogenesis, pathogenesis, epidemiology, cell biology and molecular biology of mesothelioma. During this meeting, several points were stressed, based on recent developments of research. Regarding the accuracy of the pathological diagnosis, the most discriminative markers seem at present to be the presence of keratin and vimentin contrasting with the absence of carcinoembryonic antigen (CEA) [7]. However, the use of specific monoclonaJ antibodies against mesothelioma cell membrane antigens must be encouraged, in order to allow a better discrimination between DMM and