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Neuroblastoma is the most frequent tumour of the childhood under the age of 5. The staging and the follow up are achieved by MIBG scintigraphy, considered as the method of reference, but sometimes difficult to interpret . The availability of monoclonal antibodies against the ganglioside GD2, expressed on the cell membrane of neuroblastoma and neuro-endocrine cancers offers novel tools that deserve to be carefully explored. We investigated four mouse monoclonal antibodies (3 IgG3: BW704, 7A4, 60C3, and the IgG1 variant of BW704: MAK704), on nude mice xenografted with a human neuroblastoma (REM). Sixty one nude mice were included. The three former MAbs provided tumour imaging, the best results being obtained with BW704, followed by 7A4 and 60C3. MAK704 was disappointing. A control antiphosphorylcholine antibody (P51-1) did not give any tumour image in the three tested mice. Scintigraphy ratios tumour/liver and tumour/muscle reached 20 and 100 with BW704, respectively, on the 10th day. Good imaging quality was already obtained from the 24th h. The tumour uptake, calculated from radioactivity countings of resected samples, reached 22 +/- 3% of injected dose per gramme. These results let us hope that these antibodies could also provide highly contrasted images in humans and could open the way for therapeutic applications.

A 33-year-old woman, who at 29 underwent mastectomy for a localised breast cancer (TINOMO), presented a relapse shown by a rapid rise in seric level of CEA. The classical complete work-up was negative. The location of the relapse was demonstrated by anti-CEA immunoscintigraphy. Radiotherapy, hormonotherapy and chemotherapy allowed to achieve a complete remission with normalization of CEA level and of immunoscintigraphy.

The actual interest of immunoscintigraphy for the detection of alphafetoprotein-producing liver tumors was investigated by both visual examination and quantitative analysis in 61 patients with either hepatocellular carcinoma (39 patients, group I), secondary liver cancer (11 patients, group II), or non tumoral liver (9 cirrhosis, 2 healthy liver, group III): All patients received injections of 123I-anti-alphafoetoprotein monoclonal antibodies and planar scans were performed after 28 hours. Only 18 out of 39 hepatocellular carcinoma-bearing patients had a positive scan (46 p. 100). Such a moderate sensibility was due to a striking inhibitory influence of cirrhosis: the positivity rate was 6/24 and 12/15 respectively when hepatocellular carcinoma was and was not associated with cirrhosis (p less than 0.01). Specificity was also moderate (55 p. 100) for detection of hepatocellular carcinoma in tumor-bearing patients (group I and II). In the absence of cirrhosis, the intensity of the tumoral uptake was highly correlated with high serum alphafoetoprotein level (p less than 0.001) and tumor arterial hypervascularization (p less than 0.01). Anti-alphafoetoprotein monoclonal antibody uptake by the extratumoral liver was found to be very specific of hepatocellular carcinoma since it was high in 23 out of 39 patients of group I but in only 1 out of 22 in groups II and III (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)