Medical and pediatric oncology最新文献

Background and procedure: MRP1 expression by neuroblastomas was evaluated by Northern blot analysis in 21 cell lines and 90 primary untreated tumors. Cytotoxicity assay in cell lines was performed for five anticancer drugs used in treating neuroblastoma.

Results: MRP1 expression did not correlate with drug resistance or with MYCN RNA expression in cell lines. MRP1 expression was higher in drug-sensitive cell lines established after chemotherapy relative to cell lines at diagnosis, but highly drug-resistant cell lines showed low MRP1 expression. Positive expression of MRP1 RNA in primary tumors was associated with a poorer survival relative to MRP1-negative tumors. However, MRP1 expression levels did not correlate with age, stage, MYCN amplification, or MYCN expression, and higher MRP1 expression was not associated with a worse outcome.

Conclusions: In neuroblastoma, positive MRP1 RNA expression at diagnosis has prognostic significance, but high drug resistance is conferred by mechanisms other than MRP1.

Background: Prognosis of relapsed and refractory neuroblastoma is uniformly fatal; new therapeutic approaches are needed.

Procedure: Relapsed and refractory neuroblastoma patients were treated with continuous infusion chemotherapy combined with MIBG.

Results: Over 4 years, 35 heavily pretreated patients were registered, 29 with bone or/and bone marrow metastases. Grade 3 or 4 hematologic toxicity was frequent, without toxic deaths. Sixteen patients responded. The probability of 5-year overall survival was 0.19.

Conclusions: This approach is feasible and toxicity manageable; it rescued some patients and prolonged their survival. It merits assay in newly diagnosed high-risk neuroblastoma patients.

The RARbeta/gamma-selective retinoids fenretinide and CD437 induce caspase-dependent apoptosis but generate free radicals independently of caspases. Apoptosis, but not free radical generation, induced by these retinoids is inhibited by RARbeta/gamma-specific antagonists. Both fenretinide and CD437 induce apoptosis synergistically with cisplatin, carboplatin, or etoposide. However, antioxidants inhibit this synergy to the level obtained with chemotherapeutic drugs alone, and this implies that free radical generation is important in the synergistic response. Since apoptosis induced by fenretinide or CD437 is mediated by apoptotic pathways involving RARs and/or mitochondria and differs from mechanisms of chemotherapy-induced apoptosis this may explain the strong synergistic response seen between these synthetic retinoids and chemotherapeutic drugs. These results suggest that fenretinide or CD437 may be useful adjuncts to neuroblastoma therapy.

Unlabelled: Background and Procedure High-risk neuroblastoma disease features are correlated with tumor vascularity, suggesting that angiogenesis inhibitors may be a useful addition to current therapeutic strategies. We therefore examined the efficacy of TNP-470 (TAP Pharmaceuticals, Deerfield, IL) in human neuroblastoma xenograft models.

Results: Tumor growth rate was markedly inhibited in mice receiving TNP-470 administered alone with a treatment to control ratio (T/C) at day 21 = 0.4 (P <.001). TNP-470 also significantly inhibited tumorigenicity when administered shortly after xenograft inoculation (T/C at day 30 = 0.1, P <.001) and when administered following cyclophosphamide (T/C at day 35 = 0.1, P <.001).

Conclusions: These data show that TNP-470 is a potent inhibitor of human neuroblastoma growth both alone and when given with conventional chemotherapy, suggesting that it may be a useful adjunctive therapy for high-risk neuroblastoma patients.

Background: We used phage display technology to clone human recombinant antitumor antibodies from the antibody repertoire of neuroblastoma patients immunized with cytokine-gene transduced tumor cells.

Procedure: Lymphocytes obtained from neuroblastoma patients either at diagnosis or after immunization with an autologous interleukin-2 gene transduced tumor vaccine were used to construct two human single-chain Fv (scFV) phage libraries. Tumor-reactive phage were characterized using ELISA, flow cytometry, and sequencing analysis.

Results: The initial screening after panning on neuroblastoma cells yielded a substantially higher proportion of selectivity tumor-binding phage clones derived from the immunized patients library (12.9%) than from the unvaccinated patients library (0.8%). The antibodies stained the cells from several additional pediatric malignancies, including Ewing sarcoma and rhabdomyosarcoma, in the absence of binding to any normal tissue cultures or epithelial tumor cell lines. The pattern of reactivity was different from that of antibodies recognizing other widely distributed neuroblastoma-associated antigens, suggesting recognition of a novel shared tumor antigen.

Conclusion: The human recombinant scFV antibodies reported here appear to represent a tumor-specific B-cell response induced by autologous tumor immunization and are potentially useful targeting moieties for the treatment of selected childhood tumors.

Background: The German Neuroblastoma Screening Project is the first controlled and population-based screening study to evaluate the presumed benefit of neuroblastoma mass screening at 1 year of age (10-18 months).

Procedure: Screening takes place in 6 of the 16 German states; children from the remainder serve as controls. The German Childhood Cancer Registry enables a mostly complete follow-up and detection of false-negative patients.

Results: Up to December, 1999, 1,199,165 children were examined for urinary catecholamine metabolites and 124 cases of neuroblastoma were detected preclinically, giving a detection rate of 10.3/100,000. Within this cohort, 33 false-negative cases were found.

Conclusions: The results of this screening program will be crucial for further implementation of neuroblastoma screening.