Laboratory Investigation of Non-lymphoid Malignancy

Abnormalities of genetic expression associated with malignant transformation cause a number of phenotypic changes including the production of substances by cancer cells which differ quantitatively or qualitatively from the products of normal cells. These ‘cancer markers’ or tumour associated antigens may be used as objective parameters in screening, diagnosis, staging, histopathological evaluation and monitoring treatment of non-lymphoid neoplasia. Specific and sensitive tests for alphafetoprotein, carcinoembryonic antigen, human chorionic gonadotropin and a number of other cancer markers have been developed. Established tests rely upon polyclonal heterologous antisera in radioimmunoassay or enzyme-linked immunoassay. Theoretical advantages of monoclonal antibodies in this setting have yet to be realized. Monoclonal antibodies do however show practical advantages over extensively absorbed polyclonal antisera in the histopathological evaluation of solid tumours and further progress with these reagents is expected. Studies of host-tumour immunological interactions suggest that future routine investigations of non-lymphoid neoplasia may include assessments of autochthonous reactivity.