The present role of monoclonal antibodies in the diagnosis and therapy of brain tumours.

Monoclonal antibodies already have an established role as tumour markers for use in histological and cytological diagnosis of tumours, such as to distinguish between astrocytomas, oligodendrogliomas and ependymomas. Most recently monoclonal antibodies are employed in combination with radioisotopes or cytostatic agents for radioimmuno-localisation and antibody-targeted therapy. In a preliminary study involving 12 patients with malignant gliomas the distribution of the antibody UJ = 13A labelled with J-131 has been examined. The ratio of radiolabel in normal to malignant tissue ranged from 3.1 to 12.8, however the absolute amount of labelled antibody reaching the tumour was around 0.001% of the injected dose. A phase I trial is presently conducted with an intrathecal radio-antibody therapy in cases of leptomeningeal malignancies resulting from various types of neoplasia. A clinical improvement was seen in 4 out of 5 cases, without serious side-effects. Such an antibody-guided irradiation would be most suitable for radiosensitive targets such as medulloblastomas, neuroblastomas and some tumours of the pineal region. The rapid advances that are currently made in our understanding of immunoregulation and T-cell function, as well as new technologies to gain human monoclonal antibodies by B-cell immortalisation and recombinant DNA technology and our preliminary results justify the great hope we have in immunotherapy.