Immunoglobulins associated with human tumours in vivo: IgG concentrations in eluates of colonic carcinomas.

The concentrations of IgG in acidic and 3MKCl eluates of resected colonic carcinomas and adjacent normal tissue were determined by radioimmunoassay. The mean concentration of IgG was significantly higher in both acidic and KCl eluates of primary Dukes Stage C tumours than Dukes Stage A tumours. These results provide direct evidence for increased fixation of IgG in vivo by human colonic cancers which had metastasized. Our results also raise the possibility that IgG is more tightly bound to the Stage C tumours. It is likely that this tumour-associated Ig represents antibody to tumour antigens or antigen-antibody complexes, bound to Fc receptors in the tumour.