Reduced expression of plakoglobin correlates with adverse outcome in patients with neuroblastoma.

Plakoglobin and its homologue beta-catenin are cytoplasmic proteins that mediate adhesive functions by interacting with cadherin receptors and signaling activities by interacting with transcription factors. It has been suggested that plakoglobin can suppress tumorigenicity whereas beta-catenin can act as an oncogene. We investigated the correlation between the expression pattern of N-cadherin, beta-catenin, and plakoglobin and tumor behavior in primary tumors of 20 neuroblastoma patients of all stages and in 11 human neuroblastoma cell lines. N-cadherin and beta-catenin were detected in 9 of 11 and 11 of 11 cell lines, respectively, whereas plakoglobin was undetectable or severely reduced in 6 of 11 cell lines. Tumor cells from 16 of 20 patients expressed N-cadherin and 20 of 20 patients expressed beta-catenin at levels similar to those of normal ganglion cells. Plakoglobin was undetectable in 9 of 20 tumors. Plakoglobin deficiency in the primary tumors was significantly associated with adverse clinical outcome. Five of the patients with plakoglobin-negative tumors died whereas four patients are alive without evident disease. In contrast, all patients with plakoglobin-positive tumors are alive; 2 of 11 are alive with the disease and 9 of 11 are alive without evident disease. These results suggest that down-regulation of plakoglobin may be of prognostic value for neuroblastoma patients as predictor of poor outcome.

Antiangiogenic therapy inhibits human neuroblastoma growth.

BACKGROUND: Angiogenesis plays a crucial role in the progression and metastasis of malignant solid tumors. In many types of cancer, including neuroblastoma, high tumor vascularity correlates with poor outcome. Recently, a number of angiogenic inhibitors have been identified that had antitumor activity in preclinical studies. PROCEDURE: To investigate the effect of the antiangiogenic agent TNP-470 on neuroblastoma tumor growth, we treated nude mice with TNP-470 after they were inoculated subcutaneously with 5 x 10(6) cells from the MYCN-amplified, human neuroblastoma cell line NBL-W-N. RESULTS: TNP-470 did not significantly affect tumor growth when it was administered to mice with large tumors (>600 mm3). However, when TNP-470 was administered in the setting of microscopic disease 12 hr following tumor cell inoculation, treated mice had a significantly improved tumor-free survival at 12 weeks (P < 0.001), and overall survival at 45 weeks (P < 0.001), compared to control animals. CONCLUSIONS: Our studies suggest that TNP-470 treatment may be most effective if it is administered in the setting of microscopic disease. We speculate that TNP-470 may inhibit neuroblastoma growth in children if treatment is initiated following intensive multimodality therapy, when residual disease is minimal.

Detection of unidentified chromosome abnormalities in human neuroblastoma by spectral karyotyping (SKY).

Spectral karyotyping (SKY) is a novel technique based on the simultaneous hybridization of 24 fluorescently labeled chromosome painting probes. It provides a valuable addition to the investigation of many tumors that can be difficult to define by conventional banding techniques. One such tumor is neuroblastoma, which is often characterized by poor chromosome morphology and complex karyotypes. Ten primary neuroblastoma tumor samples initially analyzed by G-banding were analyzed by SKY. In 8/10 tumors, we were able to obtain additional cytogenetic information. This included the identification of complex rearrangements and material of previously unknown origin. Structurally rearranged chromosomes can be identified even in highly condensed metaphase chromosomes. Following the SKY results, the G-banding findings were reevaluated, and the combination of the two techniques resulted in a more accurate karyotype. This combination allows identification not only of material gained and lost, but also of breakpoints and chromosomal associations. The use of SKY is therefore a powerful tool in the genetic characterization of neuroblastoma and can contribute to a better understanding of the molecular events associated with this tumor.

Amplification of immunological functions by subcutaneous injection of intermediate-high dose interleukin-2 for 2 years after autologous stem cell transplantation in children with stage IV neuroblastoma.

BACKGROUND: Immunotherapy given post-autologous stem cell transplantation may eliminate residual tumor cells escaping the conditioning protocol. METHODS: Five children suffering from stage IV neuroblastoma were treated by recombinant interleukin-2 (IL-2) post-autologous peripheral blood stem cell transplantation. The patients' peripheral mononuclear cells were monitored for CD3+ and CD56+ levels, their proliferative response and killing of various cell lines targets. RESULTS: An increase in the level of total lymphocytes, mainly due to expansion of T cells, and enhanced proliferative response to phytohemaglutinin were observed. Elevated cytotoxicity against K562 and neuroblastoma target cells was detected in four patients and against K562 targets in one patient. Toxicity included mild thrombocytopenia, and fever in four patients and mild to moderate encephalopathy which necessitated withdrawing one patient from the protocol. Three of five patients studied are alive today, one of them whose IL-2 was stopped, is in relapse. Two patients have died. CONCLUSIONS: Immunotherapy with s.c. intermediate-high dose IL-2 is feasible and results in expansion of T cells and in stimulation of killing activity against several targets including in some cases, neuroblastoma tumor cells.

Tumor angiogenesis correlates with metastatic disease, N-myc amplification, and poor outcome in human neuroblastoma.

PURPOSE: To determine if the clinical outcome of children with neuroblastoma (NB) is correlated with the degree of tumor neovascularization and to assess the relationship of stage, N-myc copy number, and histology to angiogenesis. MATERIALS AND METHODS: The vascularity of primary untreated NB from 50 patients diagnosed at a single institution between 1984 and 1994 was evaluated. An image processor was used to analyze the tumor tissue area for each histologic slide of tumor, and a vascular index (VI) was calculated, where VI = total number of vessels/mm2 of tissue area. Tumors were classified histologically according to the criteria of Shimada et al (J Natl Cancer Inst 73:405-416, 1984), and N-myc copy number was determined by Southern blot analysis. RESULTS: We found that higher VI (> 4.0) in NB strongly correlated with widely disseminated disease (P = .006) and poor survival (P < .0001). VI more than 4.0 was also statistically associated with N-myc amplification (P = .02) and unfavorable histology (P = .02). Univariate analysis demonstrated that disease stage, tumor histology, and N-myc copy number were also predictive of outcome. Cox regression analysis showed that VI provided independent prognostic information. CONCLUSION: Our studies indicate that angiogenesis may play an important role in determining the biologic behavior of NB. Antiangiogenic therapy may prove to be effective in the treatment of children with highly vascular, widely disseminated NB.