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In neuroblastoma, MYCN amplification and 11q-deletion are important, although incomplete, markers of high-risk disease. It is therefore relevant to characterize additional alterations that can function as prognostic and/or predictive markers. Using SNP-microarrays, a group of neuroblastoma patients showing amplification of one or multiple 12q loci was identified. Two loci containing CDK4 and MDM2 were commonly co-amplified, although amplification of either locus in the absence of the other was observed. Pharmacological inhibition of CDK4/6 with ribociclib or abemaciclib decreased proliferation in a broad set of neuroblastoma cell lines, including CDK4/MDM2-amplified, whereas MDM2 inhibition by Nutlin-3a was only effective in p53(wild-type) cells. Combined CDK4/MDM2 targeting had an additive effect in p53(wild-type) cell lines, while no or negative additive effect was observed in p53(mutated) cells. Most 12q-amplified primary tumors were of abdominal origin, including those of intrarenal origin initially suspected of being Wilms' tumor. An atypical metastatic pattern was also observed with low degree of bone marrow involvement, favoring other sites such as the lungs. Here we present detailed biological data of an aggressive neuroblastoma subgroup hallmarked by 12q amplification and atypical clinical presentation for which our in vitro studies indicate that CDK4 and/or MDM2 inhibition also could be beneficial.

Purpose To analyse the surgical and oncological outcome of minimally invasive surgery (MIS) for tumor nephrectomy in Wilms tumor (WT) patients. Methods WT patients from the SIOP 2001 trial, undergoing MIS for tumor nephrectomy were analyzed with regard to demographic characterization, surgical specifications, complications, and outcome. Results There were 24 children matching the inclusion criteria. Median age at operation was 40.35 months (14.3–65.4). All patients received preoperative chemotherapy. Median tumor volume was 177.5 ml at diagnosis (46.5–958) and 73.0 ml at surgery (3.8–776). There was one surgical complication (splenic injury), no intraoperative tumor rupture occurred. Abdominal stage was I in 14, II in 7, and III in 3 patients. Adequate lymph node sampling was performed in only 2 patients. One local relapse occurred. Event-free survival was 23/24, overall survival was 24/24, median follow up was 47 months (2–114). Conclusions We present the largest series so far of minimally invasive nephrectomies for nephroblastoma based on a multinational trial. Treatment results were comparable to those of open surgery; however, experience of operating surgeons was generally high. Discipline of lymph node sampling was inadequate. Based on this analysis a prospective study on MIS in nephroblastoma is planned by the SIOP Renal Tumor Study Group.

Total nephrectomy (TN) remains the standard treatment of unilateral Wilms tumors (uWT). The SIOP WT-2001 protocol allowed Nephron Sparing Surgery (NSS) for polar or peripherally non-infiltrating tumors. Inventory of the current SIOP NSS-experience. 2,800 patients with a unilateral, localized or metastatic and an unequivocal surgical technique recorded were included. All had neo-adjuvant chemotherapy and delayed surgery. In 91 (3%) NSS was performed and in 2709 TN. Data was retrieved from the SIOP WT 2001 database. NSS group contained 65% stage I tumours and the TN group 48%. Tumor volume (at diagnosis and surgery) was significantly smaller in the NSS group. Within stage III, after NSS, 7/12 (58%) had positive margins (M +), 5 with tumor negative lymph nodes (LN-). After TN, 355/712 (55%) had M + , 182 were LN-. Treatment of M+ in the NSS group resulted in two conversions to TN (one combined with radiotherapy), three patients had radiotherapy only and in two patients local therapy, if given, was not recorded. After NSS, four recurrences occurred. For localized disease the 5-year overall (OS) and event free survival (EFS) in NSS group was 100 and 94.8 (95% CI:89.9-99.9), respectively, while OS and EFS in the TN group were 94.4 (95% CI: 93.2-95.5, log-rank test P = 0.06) and 86.5 (95% CI:85.0-88.1, log-rank test P = 0.06), respectively. NSS was only performed in 3% of patients with uWT. Despite excellent survival with few relapses, the gain of nephrons needs to be weighed against the risk to induce stage III with intensified therapy

To explore possible physiologic functions for the metalloproteinase collagenase-3, we have examined its temporal and spatial expression during human fetal development. Except for mesenchymal cells in the umbilical cord at 4 weeks of gestation, signal for collagenase-3 mRNA was confined to mineralizing skeletal tissue and detected in hypertrophic chondrocytes and osteoblastic cells involved in ossification beginning at 10 weeks and continuing through gestation. These cells were also immunoreactive with collagenase-3 antiserum, indicating their ability to produce collagenase-3 protein. In osteoblastic cells, the expression of membrane-type 1 metalloproteinase and 72-kd gelatinase mRNA, which have the capacity to activate collagenase-3 in vitro, colocalized with that of collagenase-3. In postnatal tissues, collagenase-3 was re-expressed in processes involving skeletal remodeling, such as bone cysts and ectopic bone and cartilage formation. Multinucleated osteoclasts were consistently negative for collagenase-3. Furthermore, in patients with seropositive rheumatoid arthritis, expression of collagenase-3 was prominent in articular cartilage, and collagenase-3 protein was detected by immunoblotting in synovial fluids. Consistent with its substrate specificities, a plausible function for collagenase-3 in these processes is to preferentially degrade type II collagen, thus serving a role during primary ossification, in skeletal remodeling, and in destructive joint disease.

Interactions of the trk family of tyrosine kinase receptors with neurotrophins result in growth and maturational changes in neuronal cells. The continued progression, maturation, or regression of neuroblastoma, an embryonal, sympathetic nervous system-derived tumor of infants and children, might be governed by neurotrophic influences. Immunocytochemistry was utilized to evaluate TrkA, TrkB, and TrkC protein expression at the cellular level in the developing human fetal sympathetic nervous system and in a selection of neuroblastoma tumor specimens. TrkA and TrkC expression was identified in sympathetic ganglia and within the adrenal medulla, with intense TrkB expression restricted to paraganglia, of the normal developing human sympathetic nervous system. In neuroblastoma, pp140trkA expression correlated positively with favorable tumor stage (P = 0.0027) and favorable outcome (P = 0.026). No statistically significant correlation of TrkC expression with outcome was evident; however, both TrkA and TrkC expression was most apparent in tumor cells of increased differentiation. TrkB expression was primarily localized to cells within the fibrovascular tumor stroma. A model of neurotrophin receptor expression and neurotrophin reactivity with differentiation is proposed. The existence and spatial distribution of neurotrophin receptors in neuroblastoma lend supportive evidence that neurotrophic influences may be involved in tumor persistence or regression.

Overstimulation by insulin-like growth factor II is implied in several overgrowth conditions and childhood cancers. We have therefore studied spatial and temporal expression patterns of the insulin-like growth factor II gene (IGF2) and the insulin-like growth factor type 1 receptor gene during normal human development (5.5 to 23.0 weeks postfertilization). The set of cell types with the most abundant IGF2 expression correlated strikingly to the organomegaly and tumor predisposition of the Beckwith-Wiedemann syndrome. Intrauterine growth and postnatal organ weights of a prematurely born child with a full-blown syndrome are presented. The cell type-specific IGF2 expression of these organs and of multifocal Wilms' tumors from two other children affected by the Beckwith-Wiedemann syndrome were also studied. The results clarify and extend previous findings concerning human prenatal IGF2 expression and are consistent with a short range overstimulatory role of locally produced IGF II ensuing after the first trimester in the Beckwith-Wiedemann syndrome.