Photoreduction of Copper Ions Using Silica-Surfactant Hybrid and Titanium (IV) Oxide under Sulfuric Acid Conditions.

Photoreduction of Cu2+ ions to Cu metal by titanium(IV) oxide (TiO2) was conducted in the presence of a silica-surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2p1/2 and 2p3/2 in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer-Emmett-Teller specific surface area from 36 and 45 m2/g for the silica-surfactant and TiO2, respectively, to 591 m2/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier-transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO2 was used solely. Therefore, this study indicated that the photoreduction of Cu2+ ions to Cu metal by TiO2 was facilitated under the sulfuric acid medium, where the surfactants extracted from silica-surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO2. Thus, this study presents a new application of the conversion of a silica-surfactant hybrid into mesoporous silicas.

Encapsulation of Cu nanoparticles in nanovoids of plate-like silica sodalite through interlayer condensation of Cu2+ ion-exchanged layered silicate RUB-15.

The interlayer condensation of layered silicates is a unique method for synthesizing zeolites and is effective for the introduction of metal species into platy zeolite frameworks. Layered silicate RUB-15 is a useful starting material because metal ions can be introduced between the layers and zeolite frameworks (all-silica SOD-type zeolite; silica sodalite) can be formed through interlayer condensation. In this study, Cu ions were intercalated into layered silicate RUB-15, and metal Cu nanoparticles were formed in the nanovoids of silica sodalite by a simple heat treatment in an inert atmosphere. Both interlayer condensation and the reduction of Cu2+ ions were confirmed by in situ XRD analysis performed during the heat treatment. The residual interlayer tetramethylammonium ions played two roles: the control of stacking sequence in the interlayer condensation and the reduction of Cu2+ ions. The formed Cu nanoparticles were stable in air atmosphere because of their confinement in the nanovoids of the sodalite frameworks.

A prospective evaluation of liquid biopsy for detecting MYCN amplification in neuroblastoma patients.

BACKGROUND: Our previous study reported a method for determining MYCN gene amplification (MNA) status using cell-free DNA in serum. We prospectively analyzed the serum MNA status using sera obtained before the initial diagnosis from patients with neuroblastoma and evaluated the utility of this method. METHODS: Eighty patients were enrolled in the study. The serum MYCN/NAGK ratio was assessed for all cases. RESULTS: Fifteen cases showed serum MNA, while 65 did not. Of the 80 total patients, tumor samples for a genetic analysis were not obtained from 27 due to the patients' condition or other reasons. For the 43 of 80 cases that had both serum and tumor samples analyzed, the serum-based MNA status matched to tumor-based MNA status (P < 0.001). The sensitivity and the specificity were 100%, respectively. Seven of 15 cases who diagnosed as MNA by serum-based MNA status were <18 months of age, and tumor samples were not obtained from 4 of these cases. Based on the serum MNA status, these cases were able to start treatment immediately. The 4-year event-free survival rates of cases with and without MNA in sera were 37.5% and 84.8%, respectively (P < 0.001). CONCLUSION: The serum-based MNA status was useful for precisely predicting the MNA status in tumor and it has clinical benefits for predicting risk stratification in patients for whom obtaining tumor samples is difficult.

Serum-Based Quantification of MYCN Gene Amplification in Young Patients with Neuroblastoma: Potential Utility as a Surrogate Biomarker for Neuroblastoma.

We previously developed a method for determining MYCN gene amplification status using cell-free DNA fragments released from cancer cells into the blood of patients with neuroblastoma (NB). Here, we analyzed the relationship between MYCN amplification (MNA) status and neuroblastoma prognosis. We screened serum samples from 151 patients with NB for MNA, using real-time quantitative PCR, and compared the results with MYCN status determined using paired tumor samples. We additionally investigated whether MNA status correlates with patient survival. When a cut-off value of 5 was used, serum-based MNA analysis was found to show good sensitivity (86%) and very high specificity (95%). The sensitivities for stage 1 and 2 might be acceptable, even though it is not as good as for stage 3 and 4 (67% for stage 1 and 2, 92% for stage 3, and 87% for stage 4). MNA status correlated with overall survival in our cohort of 82 patients, with survival data available (p < 0.01). The hazard ratio of MNA status was 4.98 in patients diagnosed at less than 18 months of age (95% confidence interval, 1.00-24.78), and 1.41 (95% confidence interval, 0.63-3.14) for those diagnosed at 18 months of age or older. Serum-based MNA analysis is rapid and non-invasive compared with tumor-based MNA analysis, and has potential to predict tumor MNA status. There is still a room to improve the sensitivity of the test for tumors of stages 1 and 2, nonetheless this assay might help to determine therapeutic strategies prior to tumor biopsy, especially for patients with a life-threatening condition, as well as for patients of less than 18 months of age whose risk-grouping and treatment allocation depends on their MNA status.

A MYCN-amplified cell line derived from a long-term event-free survivor among our sixteen established neuroblastoma cell lines.

Although more than 110 neuroblastoma (NB) cell lines have been established, there have been neither reports on the rate of success to establish NB cell lines, nor well-documented NB cell lines from long-term-survivors. We attempted to establish NB cell lines from 114 patients. Sixteen NB cell lines were established from 12 patients. The success rates to establish cell lines were 1.4% (1/70) from patients in early stages, 25.0% (11/44) from those in advanced stages, and 10.5% (12/114) from those in all stages respectively. Eleven of these 12 patients eventually died. The surviving patient, who was in stage 4 with MYCN-amplification, has been event-free for 19 years after completing therapy. The serum MYCN DNA level in patient TK was very high before therapy, decreased after chemotherapy, and has remained at the normal levels until now. The gene expression profiling of the primary tumor and the K-N-TK cell line was analyzed with an NB-specific cDNA microarray, and indicated that the probability of 5-year survival was extremely low. Microarray-based comparative genomic hybridization (CGH) analysis indicated that genomic aberration profiles of the cell line were uncommon, with MYCN amplification, 17q gain and 11q loss. A unique KP-N-TK cell line, established from an event-free survivor, will be a useful tool for investigating how a patient can survive a tumor with an extremely poor prognosis.

Immunohistochemical analysis of the proteolytic enzyme subtilase in the digestive organs of the sea urchin Strongylocentrotus intermedius.

Subtilase, a major protease in the short-spined sea urchin (Strongylocentrotus intermedius), was isolated and used as antigen for the subsequent production of a specific polyclonal antibody. Immunoreactive cells were observed by immunohistochemical analysis in granules in the anterior and posterior stomach and the anterior intestine. These granules, which were most numerous in the anterior stomach, also stained intensely with methylene blue-Azure II. However, granules in cells of the esophagus, posterior intestine, and rectum were not stained by this antibody. We conclude that subtilase mainly localizes in the stomach and anterior intestine of the sea urchin.

Preoperative analysis of 11q loss using circulating tumor-released DNA in serum: a novel diagnostic tool for therapy stratification of neuroblastoma.

Allelic deletion of the long arm of chromosome 11 (11q loss) is closely associated with the prognosis of neuroblastoma (NB). Here we examined 11q loss using tumor-released DNA fragments in the sera of 24 cases. The allelic intensity score of a panel of polymorphic markers in 11q23 in serum DNA was significantly different between the 11q loss-positive group and the11q loss-negative group. The 11q loss-positive and -negative groups did not overlap when a cut-off value of 0.5 was chosen for the allelic intensity score. Our serum-based 11q loss analysis could predict the allelic status of 11q in tumors.

Circulating methylated-DCR2 gene in serum as an indicator of prognosis and therapeutic efficacy in patients with MYCN nonamplified neuroblastoma.

BACKGROUND: MYCN amplification (MNA) in neuroblastoma is a strong indicator of poor prognosis. However, some MYCN nonamplified (non-MNA) cases show poor outcomes, and examining the status of the gene requires an operation, which may have surgical complications. Therefore, a new marker is needed to identify cases of non-MNA neuroblastomas with poor prognoses using less risky procedures. Aberrant hypermethylation of the DCR2 promoter has recently been associated with rapidly progressing neuroblastoma. We aimed to develop a noninvasive DCR2 methylation assay for patients with neuroblastoma using serum DNA, which predominantly originates from tumor-released DNA. METHODS: Using DNA-based real-time PCR, we simultaneously quantified a methylated-DCR2 specific sequence (M) and a reference sequence (R) located in the promoter region in serum DNA, and evaluated DCR2 methylation status as M/R ratios in 86 patients with neuroblastoma. RESULTS: Serum DCR2 M/R ratios were strongly correlated with those in the tumor (r=0.67; P=0.002). DCR2 methylation was associated with stage both in the whole neuroblastoma group and in the non-MNA group (P<0.001), and DCR2-methylated patients showed significantly poorer 5-year event-free survival in the whole neuroblastoma group (43% versus 84%; P<0.001), especially in the non-MNA group (12% versus 96%;P<0.001). Among five DCR2-methylated patients whose clinical courses were followed, serum M/R ratios were close to 0 in the patients in remission, whereas the ratios increased in patients who relapsed. CONCLUSIONS: Detection of methylated-DCR2 in serum DNA has promise as a noninvasive assay for predicting prognosis and therapeutic efficacy in neuroblastoma, especially in non-MNA cases. Furthermore, it might be a sensitive marker of tumor recurrence in DCR2-methylated cases.

Prognostic value of the co-expression of carbonic anhydrase IX and vascular endothelial growth factor in patients with clear cell renal cell carcinoma.

This study aimed to investigate whether the expression of carbonic anhydrase IX (CAIX) is associated with the expression of vascular endothelial growth factor (VEGF) and whether the co-expression of the two correlates with survival outcome in clear cell renal cell carcinoma (ccRCC). The expression of CAIX and VEGF was evaluated immunohistochemically in 122 paraffin-embedded ccRCC specimens. The clinical significance of these markers in relation to disease-specific survival (DSS) was analyzed. Patients with a low expression of CAIX had a significantly worse prognoses than those with a high expression (p=0.0005). Inversely, patients with a high expression of VEGF had a significantly worse prognoses than the patients with a low expression (p=0.0030). Furthermore, CAIX expression significantly stratified the DSS of patients with high-stage (p=0.0001), high-grade (p=0.0392), low-grade (p=0.0273), metastasis (p=0.0034), no metastasis (p=0.0303) and ECOG-PS=0 (p=0.0003). VEGF expression significantly predicted the survival of patients with low-grade (p=0.0003), high-stage (p=0.0401) and ECOG-PS=0 (p=0.0063). A multivariate Cox regression analysis showed that tumor stage (p=0.0054), metastasis (p=0.0193), ECOG-PS (p=0.0065) and CAIX expression (p=0.0001) were independent prognostic factors of DSS. Since CAIX and VEGF expression correlated inversely (p=0.0032), the prognostic value of the co-expression of CAIX-VEGF was evaluated. Multivariate analysis revealed that the co-expression was an independent prognostic factor of DSS (p=0.0002). In addition, the co-expression was able to stratify DSS into three risk groups: high-risk, intermediate-risk and low-risk (p<0.0001). In patients with ccRCC, CAIX and VEGF expression correlated inversely. Independent expression of CAIX and a co-expression of CAIX-VEGF were found to be independent predictors of DSS. Furthermore, the co-expression data for CAIX-VEGF provide more accurate prognostic information than the individual data. This information may be useful for survival prediction and risk stratification of patients with ccRCC.

CHD5, a tumor suppressor gene deleted from 1p36.31 in neuroblastomas.

BACKGROUND: Neuroblastomas are characterized by hemizygous 1p deletions, suggesting that a tumor suppressor gene resides in this region. We previously mapped the smallest region of consistent deletion to a 2-Mb region of 1p36.31 that encodes 23 genes. Based on mutation analysis, expression pattern, and putative function, we identified CHD5 as the best tumor suppressor gene candidate. METHODS: We determined the methylation status of the CHD5 gene promoter in NLF and IMR5 (with 1p deletion) and SK-N-SH and SK-N-FI neuroblastoma cell lines using methylation-specific sequencing and measured CHD5 mRNA expression by reverse transcription polymerase chain reaction in cells treated with or without 5-aza-2-deoxycytidine, an inhibitor of DNA methylation. We transfected the cells with CHD5 and antisense (AS) CHD5 DNA to assess the effect of CHD5 overexpression and suppression, respectively, on colony formation in soft agar and growth of xenograft tumors in athymic mice. We also analyzed the association of CDH5 expression with outcomes of 99 neuroblastoma patients. Statistical tests were two-sided. RESULTS: CHD5 expression was very low or absent in neuroblastoma cell lines. The CHD5 promoter was highly methylated in NLF and IMR5 lines, and CHD5 expression increased after treatment with 5-aza-2-deoxycytidine. Clonogenicity and tumor growth were abrogated in NLF and IMR5 cells overexpressing CHD5 compared with antisense CHD5 (clonogenicity: mean no. of colonies per plate, NLF-CHD5, 43 colonies, 95% confidence interval [CI] = 35 to 51 colonies, vs NLF-CHD5-AS, 74 colonies, 95% CI = 62 to 86 colonies, P < .001; IMR5-CHD5, 11 colonies, 95% CI = 2 to 20 colonies, vs IMR5-CHD5-AS, 39 colonies, 95% CI = 17 to 60 colonies, P = .01; tumor growth, n = 10 mice per group: mean tumor size at 5 weeks, NLF-CHD5, 0.36 cm(3), 95% CI = 0.17 to 0.44 cm(3), vs NLF-CHD5-AS, 1.65 cm(3), 95% CI = 0.83 to 2.46 cm(3), P = .002; IMR5-CHD5, 0.28 cm(3), 95% CI = 0.18 to 0.38 cm(3), vs IMR5-CHD5-AS, 1.15 cm(3), 95% CI = 0.43 to 1.87 cm(3); P = .01). High CHD5 expression was strongly associated with favorable event-free and overall survival (P < .001), even after correction for MYCN amplification and 1p deletion (P = .027). CONCLUSIONS: CHD5 is the strongest candidate tumor suppressor gene that is deleted from 1p36.31 in neuroblastomas, and inactivation of the second allele may occur by an epigenetic mechanism.

Effects of PAX3-FKHR on malignant phenotypes in alveolar rhabdomyosarcoma.

The malignancy of alveolar rhabdomyosarcoma (ARMS) has been linked to expression of the PAX3-FKHR chimeric gene. To understand the effect of this gene, we used RNAi to knock down its expression (without affecting the expressions of either PAX3 or FKHR) in human ARMS cell lines. Down-regulating PAX3-FKHR caused (a) tumor cells to accumulate in the G1 phase, inhibiting the rate of cellular proliferation, (b) a reduction in the levels of the MET, reducing cell motility stimulated by HGF, and (c) induction of the myogenic differentiation gene, myogenin, and muscle differentiation (morphologic change and the expression of muscle specific proteins, desmin, and myosin heavy chain). These results suggest that PAX3-FKHR in ARMS cells promotes malignant phenotypes such as proliferation, motility, and to suppress differentiation.

De novo identification of MIZ-1 (ZBTB17) encoding a MYC-interacting zinc-finger protein as a new favorable neuroblastoma gene.

PURPOSE: Neuroblastoma is a childhood cancer that exhibits either a favorable or an unfavorable phenotype. Favorable neuroblastoma genes (EPHB6, EFNB2, EFNB3, NTRK1, and CD44) are genes whose high-level expression predicts favorable neuroblastoma disease outcome. Accordingly, the forced expression of these genes or their reactivation by gene silencing inhibitors in unfavorable neuroblastoma cells results in suppression of tumor growth and metastases. This study was undertaken to design an experimental strategy to identify additional favorable neuroblastoma genes. EXPERIMENTAL DESIGN: Favorable neuroblastoma gene candidates were first identified by gene expression profiling analysis on IMR5 neuroblastoma cells treated with inhibitors of DNA methylation and histone deacetylase against the untreated control cells. Among the candidates, we focused on MIZ-1, which encodes a MYC-interacting zinc-finger protein, because it is known to enhance the expression of growth suppressive genes, such as CDKN1A. RESULTS: High-level MIZ-1 expression was associated with favorable disease outcome of neuroblastoma (P = 0.0048). Forced MIZ-1 expression suppressed in vitro growth of neuroblastoma cell lines. High MIZ-1 expression was correlated with the small-size neuroblastoma xenografts treated with gene silencing inhibitors or a glucocorticoid. In addition, forced MIZ-1 expression enhanced the expression of CD44 and EFNB2 in neuroblastoma cell lines in vitro. Furthermore, MIZ-1 expression was positively correlated with the expression of favorable neuroblastoma genes (EFNB2, EFNB3, EPHB6, and NTRK1) in the human neuroblastoma xenograft therapeutic models. CONCLUSION: MIZ-1 is a new favorable neuroblastoma gene, which may directly or indirectly regulate the expression of other favorable neuroblastoma genes.

Induction of apoptosis by an inhibitor of EGFR in neuroblastoma cells.

We aimed to examine the expression of EGFR in neuroblastoma tissues and to investigate the antitumor activity of a selective EGFR-tyrosine kinase inhibitor, gefitinib, on neuroblastoma. The expression of EGFR was detected in each of two tumor tissues by immunohistochemistry and eight of 10 cell lines by Western blotting. Gefitinib inhibited EGFR-phosphorylation and in vitro cell growth (IC(50): approximately 1.2 microM), and a high concentration of gefitinib (20-30 microM) induced apoptosis in vitro. This is the first report that EGFR protein is expressed on the cell surface in neuroblastoma tissues and in cell lines. We also demonstrated an EGFR inhibitor induced apoptosis on neuroblastoma cells. Our results suggest the feasibility of targeting EGFR as a novel strategy against neuroblastoma.

Immunohistochemical analysis with multiple antibodies in search of prognostic markers for clear cell renal cell carcinoma.

OBJECTIVES: To simultaneously analyze multiple biologic markers to identify strong prognostic markers for disease-specific survival of patients with clear cell renal cell carcinoma (ccRCC). METHODS: The expression of Ki-67, p53, bcl-2, cyclin-D1, caveolin-1, vascular endothelial growth factor, and HER-2 was evaluated in 119 paraffin-embedded ccRCC specimens using immunohistochemistry. The clinical significance of these markers in relation to disease-specific survival was analyzed. RESULTS: On univariate analysis, high-level staining for Ki-67 (P <0.0001), p53 (P = 0.0029), vascular endothelial growth factor (P = 0.0062), and caveolin-1 (P = 0.0396) was associated with decreased survival, but high-level staining for bcl-2 (P <0.0001) and cyclin-D1 (P = 0.0002) was associated with increased survival. Only HER-2 expression was not related to survival (P = 0.1131). Multivariate analysis revealed the following independent predictors of disease-specific survival: expression of p53 (P = 0.0059) or bcl-2 (P = 0.0413) in all cases of ccRCC; expression of p53 (P = 0.0043) or bcl-2 (P = 0.0227) in cases of grade 1-2 disease; and expression of p53 (P = 0.0207) in cases with metastasis at surgery. CONCLUSIONS: Of the seven markers reviewed, p53 and bcl-2 were strong prognostic factors in all cases and in cases of grade 1-2 ccRCC. Only p53 attained independent prognostic significance in metastatic ccRCC. This information could prove useful in selecting markers to predict for survival and plan therapy for patients with ccRCC.

Spontaneous disappearance of multiple lung metastases after nephroureterectomy from sarcomatoid carcinoma of the renal pelvis: a case report.

We report a case in which lung metastases disappeared spontaneously after nephroureterectomy from sarcomatoid carcinoma of the renal pelvis. A 58-year-old man presented with gross hematuria. Computed tomography (CT) revealed a left renal tumor and multiple lung metastases. Intravenous pyelography revealed a filling defect in the upper renal calyx. Urine cytology was positive. Left renal pelvic cancer was diagnosed and nephroureterectomy performed. The resected specimen was diagnosed pathologically as sarcomatoid carcinoma of the renal pelvis. Approximately 5 months later, CT revealed that the lung metastases had disappeared. There has been no evidence of disease for 46 months postoperatively.

Endourological re-establishment of a disrupted infundibulum after renal laceration.

We report a case of severe urinary extravasation after renal contusion and its successful management by endoscopic creation of a neoinfundibulum. When the stenotic infundibulum cannot be traversed with a guide wire, creation of a new infundibulum will offer a secure alternative for accessing the collecting system.

Fusion between CIC and DUX4 up-regulates PEA3 family genes in Ewing-like sarcomas with t(4;19)(q35;q13) translocation.

Ewing's family tumors (EFTs) are highly malignant tumors arising from bone and soft tissues that exhibit EWS-FLI1 or variant EWS-ETS gene fusions in more than 85% of the cases. Here we show that CIC, a human homolog of Drosophila capicua which encodes a high mobility group box transcription factor, is fused to a double homeodomain gene DUX4 as a result of a recurrent chromosomal translocation t(4;19)(q35;q13). This translocation was seen in two cases of soft tissue sarcoma diagnosed as Ewing-like sarcoma. CIC-DUX4 exhibits a transforming potential for NIH 3T3 fibroblasts, and as a consequence of fusion with a C-terminal fragment of DUX4, CIC acquires an enhanced transcriptional activity, suggesting that expression of its downstream targets might be deregulated. Gene expression analysis identified the ETS family genes, ERM/ETV5 and ETV1, as potential targets for the gene product of CIC-DUX4. Indeed, CIC-DUX4 directly binds the ERM promoter by recognizing a novel target sequence and significantly up-regulates its expression. This study clarifies the function of CIC and its role in tumorigenesis, as well as the importance of the PEA3 subclass of ETS family proteins in the development of EFTs arising through mechanisms different from those involving EWS-ETS chimeras. Moreover, the study identifies the role of DUX4 that is closely linked to facioscapulohumeral muscular dystrophy in transcriptional regulation.

Migration of prostate brachytherapy seeds to the vertebral venous plexus.

PURPOSE: We report two cases of seed migration to the vertebral venous plexus after iodine-125 (I-125) transperineal interstitial permanent prostate brachytherapy. METHODS AND MATERIALS: Case 1: A 67-year-old Japanese man underwent percutaneous transperineal interstitial permanent prostate brachytherapy at our institution. Three months after brachytherapy, routine followup kidney-urinary bladder (KUB) radiography showed two seeds that had migrated to the pelvic area and were overlapped by sacral bone. It was very difficult to detect the seeds by visceral CT, because seeds were in contact with to vertebral bone, and seeds and bone were of the same CT value in visceral CT. But bone CT could distinguish seeds and bone, and it showed seed migration to the vertebral venous plexus in the sacral vertebral canal. Case 2: A 75-year-old Japanese man underwent percutaneous transperineal interstitial permanent prostate brachytherapy at our institution. The day after seed implantation, routine followup KUB radiography showed that a seed had migrated to the pelvic area and was overlapped by sacral bone. Bone CT clearly showed seed migration to the vertebral venous plexus in the vertebral canal in comparison with visceral CT. RESULTS: Seeds that have migrated to the vertebral venous plexus are difficult to be detected by visceral CT or KUB radiography. In visceral CT, it is difficult to distinguish seed and bone, especially when they are touching each other because they have the same CT value in visceral CT. It is therefore necessary to perform bone CT to detect such migrating seeds. CONCLUSIONS: To our knowledge, this is the first report of seed migration to the vertebral venous plexus after prostate brachytherapy. We thought that seeds migrate to the vertebral plexus via the pelvic venous pathway. If seed migration to the pelvic area and the overlapped sacral bone area is found after brachytherapy, bone CT should be performed, especially when it is difficult to detect the seed in visceral CT.

Prediction of MYCN amplification in neuroblastoma using serum DNA and real-time quantitative polymerase chain reaction.

PURPOSE: MYCN amplification (MNA) indicates a poor prognosis in neuroblastoma (NB) and is routinely assayed for therapy stratification. We aimed to develop a diagnostic tool to predict MYCN status using serum DNA, which, in cancer patients, predominantly originates from tumor-released DNA. PATIENTS AND METHODS: Using DNA-based real-time quantitative polymerase chain reaction, we simultaneously quantified MYCN (2p24) and a reference gene, NAGK (2p12), and evaluated MYCN copy number as an MYCN/NAGK (M/N) ratio in 87 NB patients whose MYCN status had been determined by Southern blotting. Of these patients, 17 had MYCN-amplified NB, and 70 had nonamplified NB. RESULTS: The serum M/N ratio in the MNA group (median, 199.32; range, 17.1 to 901.6; 99% CI, 107.0 to 528.7) was significantly (P < .001) higher than the ratio in the non-MNA group (median, 0.87; range, 0.25 to 4.6; 99% CI, 0.82 to 1.26; Mann-Whitney U test). The sensitivity and specificity of the serum M/N ratio as a diagnostic test were both 100% when the serum M/N ratio cutoff was set at 10.0. Among six MNA patients whose clinical courses were followed, the serum ratios decreased to the normal range in the patients in remission (n = 3), whereas the ratios increased to high levels in the patients who relapsed (n = 2) or failed to achieve remission (n = 1). CONCLUSION: Measurement of the serum M/N ratio seems to be a promising method for accurately assessing MYCN status in NB, although a larger set of patients needs to be examined to confirm this result.