Testicular cancer: B5, a new tumour marker

Tumour markers which occur in blood or urine are of value in the management of cancer patients because they allow disease status to be monitored by non-invasive techniques at low cost. An antigen, 'B5', on erythrocytes has been shown to become enhanced when cancer develops, regardless of tumour type, and thus the B5 antigen may be utilised as a 'universal' tumour marker. A simple haemagglutination test gives reliable quantitative assessment of the B5 marker status. Here, serial measurements of B5 status in 63 patients presenting with testicular cancer confirms a preliminary finding that both teratoma and seminoma are marked by B5. Of 28 patients with seminoma, 2 had a raised BHCG, whilst 20 (71%) were B5-positive, including 13 of 20 patients with stage-1 disease. After successful treatment, the large majority of patients showed a significant downward shift in their B5 status. Control subjects differed in that their B5 status remained constant and was often also very weak.