[CA 19-9 in early cancers of the bronchi. Comparison with the carcinoembryogenic antigen].

CA 19-9 (monosialoganglioside) isolated from adenocarcinomas of the gastrointestinal tract can be measured in biological fluids using a monoclonal antibody assay. A radioimmunometric assay kit produced by ORIS Industrie has been used to measure the serum level of CA 19-9 in lung cancer and the results have been compared to that of carcinoembryonic antigen. The combination of the 2 markers increase by 10% the number of subjects with a raised marker. There is no significant relationship between the levels of CA 19-9, the type of tumour or the tumour stage. The recognition of the sialic acid as an epitope by the monoclonal antibody appears to be responsible for the false positive results in non-malignant lung disease.