[Antibodies to Forssman antigen in patients with cancer of the gastrointestinal tract and breast].

Blood sera of 103 normal persons, 104 patients with malignant and 33 patients with benign tumors of different sites, 28 patients with inflammatory diseases of the gastro-intestinal tract and female sexual organs were examined to demonstrate antibodies to Forssman's antigen (FA) by means of the microhemagglutination test with sheep red blood cells. It was established that reduction in the amount of antibodies to FA was the most characteristic for gastro-intestinal carcinomas and to a lesser degree for breast cancers and that it was sporadically encountered in normal persons with non-cancerous pathology. The number of patients with low titres of antibodies to FA increased as the cancerous process progressed.