The p73 gene is a p53 homologue which induces apoptosis and inhibits cell proliferation. Although p73 maps at 1p36.3 and is frequently deleted in neuroblastoma (NB), it does not act as a classic oncosuppressor gene. In developing sympathetic neurons of mice, p73 is predominantly expressed as a truncated anti-apoptotic isoform (DNp73), which antagonizes both p53 and the fulllength p73 protein (TAp73). This suggests that p73 may be part of a complex tumor-control mechanism. To determine the role of DNp73 in NB we analyzed the pattern of expression of this gene in vivo and evaluated the prognostic significance of its expression. Our results indicate that DNp73 expression is associated with reduced apoptosis in a NB tumor tissue. Expression of this variant in NB patients significantly correlates with age at diagnosis and VMA urinary excretion. Moreover it is strongly associated with reduced survival (HR=7.93; P50.001) and progression-free survival (HR=5.3; P50.001) and its role in predicting a poorer outcome is independent from age, primary tumor site, stage and MYCN amplification (OS: HR=5.24, P=0.012; PFS: HR=4.36, P=0.005). In conclusion our data seem to indicate that DNp73 is a crucial gene in neuroblastoma pathogenesis.

BackgroundNeuroblastoma is characterized by substantial clinical heterogeneity. Despite intensive treatment, the survival rates of high-risk neuroblastoma patients are still disappointingly low. Somatic chromosomal copy number aberrations have been shown to be associated with patient outcome, particularly in low- and intermediate-risk neuroblastoma patients. To improve outcome prediction in high-risk neuroblastoma, we aimed to design a prognostic classification method based on copy number aberrations.MethodsIn an international collaboration, normalized high-resolution DNA copy number data (arrayCGH and SNP arrays) from 556 high-risk neuroblastomas obtained at diagnosis were collected from nine collaborative groups and segmented using the same method. We applied logistic and Cox proportional hazard regression to identify genomic aberrations associated with poor outcome.ResultsIn this study, we identified two types of copy number aberrations that are associated with extremely poor outcome. Distal 6q losses were detected in 5.9% of patients and were associated with a 10-year survival probability of only 3.4% (95% confidence interval [CI] = 0.5% to 23.3%, two-sided P = .002). Amplifications of regions not encompassing the MYCN locus were detected in 18.1% of patients and were associated with a 10-year survival probability of only 5.8% (95% CI = 1.5% to 22.2%, two-sided P < .001).ConclusionsUsing a unique large copy number data set of high-risk neuroblastoma cases, we identified a small subset of high-risk neuroblastoma patients with extremely low survival probability that might be eligible for inclusion in clinical trials of new therapeutics. The amplicons may also nominate alternative treatments that target the amplified genes.

Background:In neuroblastoma (NB), the presence of segmental chromosome alterations (SCAs) is associated with a higher risk of relapse.Methods:In order to analyse the role of SCAs in infants with localised unresectable/disseminated NB without MYCN amplification, we have performed an array CGH analysis of tumours from infants enroled in the prospective European INES trials.Results:Tumour samples from 218 out of 300 enroled patients could be analysed. Segmental chromosome alterations were observed in 11%, 20% and 59% of infants enroled in trials INES99.1 (localised unresectable NB), INES99.2 (stage 4s) and INES99.3 (stage 4) (P<0.0001). Progression-free survival was poorer in patients whose tumours harboured SCA, in the whole population and in trials INES99.1 and INES99.2, in the absence of clinical symptoms (log-rank test, P=0.0001, P=0.04 and P=0.0003, respectively). In multivariate analysis, a SCA genomic profile was the strongest predictor of poorer progression-free survival.Conclusion:In infants with stage 4s MYCN-non-amplified NB, a SCA genomic profile identifies patients who will require upfront treatment even in the absence of other clinical indication for therapy, whereas in infants with localised unresectable NB, a genomic profile characterised by the absence of SCA identifies patients in whom treatment reduction might be possible. These findings will be implemented in a future international trial.

BACKGROUNDNeuroblastoma (NB) occurs rarely during adolescence, and information is scarce on its characteristics and clinical course in this age group.METHODSPatients with NB who were included in the Italian Neuroblastoma Registry were considered for the current study. The clinical characteristics and survival of adolescents (age at diagnosis between 10 yrs and 18 yrs) were compared with those of children (ages 1–9 yrs). Infants (age < 1 yr) were excluded because of their well known favorable clinical course.RESULTSBetween 1116 children and 53 adolescents who were evaluated, no differences were documented with regard to the primary tumor site and the prevalence of advanced stage at diagnosis. If only patients with Stage IV NB were considered, then adolescents were less likely to be diagnosed with bone/bone marrow metastases (77%) compared with children (94%; P = 0.038), but adolescents were more likely to have metastases at unusual sites, such as the lung parenchyma or the central nervous system (23% vs. 7%, respectively; P = 0.005). With regard to biologic characteristics, adolescents did not differ significantly from children, although they always had a lower prevalence of unfavorable markers. In particular, MYCN amplification was documented in 21% of children and in 11% of adolescents (P = 0.173). At age 10 years, adolescents had a 20% overall survival rate and a 22% event‐free survival rate. Adolescents who had resectable disease had a 73% overall survival rate, which was worse compared with the rate among children with the same disease stage (89%), although the difference did not reach statistical significance (P = 0.159). No differences in survival were observed among patients with Stage IV NB, and adolescents had a probability of survival almost identical to that among children (6% vs. 16%, respectively; P = 0.481). However, when the analysis was restricted to events that occurred after patients developed a recurrence, even if the final outcome was poor for both groups, the difference was statistically significant (P = 0.022) mostly because of the more indolent disease course observed among the adolescents. This effect was even more evident for patients with Stage IV NB. When the 6‐year cut‐off point was used to separate children from adolescents, a significantly worse overall survival rate (P = 0.036) was documented for adolescents who had resectable disease (81% vs. 93% in children).CONCLUSIONSNB in adolescents had clinical and biologic characteristics similar to those observed among children. The clinical course of NB probably is correlated significantly with age at diagnosis, but information is scarce on the role of the biologic risk factors in this age group. The authors were able to identify a group of patients with a cut‐off age between 6 years and 10 years that had a more indolent course but a worse prognosis. Cancer 2006. © 2006 American Cancer Society.

This study demonstrated the importance of revealing the difficulties and limitations for each technique and problems in interpreting results, which are crucial for therapeutic decisions. Moreover, it led to the formulation of guidelines that are applicable to all kinds of tumors and that contain the standardization of techniques, including the exact determination of the tumor cell content. Finally, the group has developed a common terminology for molecular-genetic results.