How ten-years of reirradiation for paediatric high-grade glioma may shed light on first line treatment.

PURPOSE: Recurrence incidence for paediatric/adolescent high-grade glioma (HGG) exceeds 80%. Reirradiation (reRT) palliates symptoms and delays further progression. Strategies for reRT are scarce: we retrospectively analysed our series to develop rational future approaches. METHODS: We re-evaluated MRI + RT plans of 21 relapsed HGG-patients, accrued 2010-2021, aged under 18 years. All underwent surgery and RT + chemotherapy at diagnosis. Pathologic/molecular re-evaluation allowed classification based on WHO 2021 criteria in 20/21 patients. Survival analyses and association with clinical parameters were performed. RESULTS: Relapse after 1st RT was local in 12 (7 marginal), 4 disseminated, 5 local + disseminated. Re-RT obtained 8 SD, 1 PR, 1PsPD, 1 mixed response, 10 PD; neurological signs/symptoms improved in 8. Local reRT was given to 12, followed again by 6 local (2 marginal) and 4 local + disseminated second relapses in 10/12 re-evaluated. The 4 with dissemination had 1 whole brain, 2 craniospinal irradiation (CSI), 1 spine reRT and further relapsed with dissemination and local + dissemination in 3/four assessed. Five local + disseminated tumours had 3 CSI, 1 spine reRT, further progressing locally (2), disseminated (1), n.a. (1). Three had a third RT; three were alive at 19.4, 29, 50.3 months after diagnosis. Median times to progression/survival after re-RT were 3.7 months (0.6-16.2 months)/6.9 months (0.6-17.9 months), improved for longer interval between 1st RT and re-RT (P = 0.017) and for non-PD after reRT (P < 0.001). First marginal relapse showed potential association with dissemination after re-RT (P = 0.081). CONCLUSIONS: This is the biggest series of re-RT in paediatric HGG. Considering the dissemination observed at relapse, our results could prompt the investigation of different first RT fields in a randomized trial.

Proteomic analysis of cerebrospinal fluid from children with central nervous system tumors identifies candidate proteins relating to tumor metastatic spread.

Central nervous system (CNS) tumors are the most common solid tumors in childhood. Since the sensitivity of combined cerebrospinal fluid (CSF) cytology and radiological neuroimaging in detecting meningeal metastases remains relatively low, we sought to characterize the CSF proteome of patients with CSF tumors to identify biomarkers predictive of metastatic spread. CSF samples from 27 children with brain tumors and 13 controls (extra-CNS non-Hodgkin lymphoma) were processed using core-shell hydrogel nanoparticles, and analyzed with reverse-phase liquid chromatography/electrospray tandem mass spectrometry (LC-MS/MS). Candidate proteins were identified with Fisher's exact test and/or a univariate logistic regression model. Reverse phase protein array (RPPA), Western blot (WB), and ELISA were used in the training set and in an independent set of CFS samples (60 cases, 14 controls) to validate our discovery findings. Among the 558 non-redundant proteins identified by LC-MS/MS, 147 were missing from the CSF database at http://www.biosino.org. Fourteen of the 26 final top-candidate proteins were chosen for validation with WB, RPPA and ELISA methods. Six proteins (type 1 collagen, insulin-like growth factor binding protein 4, procollagen C-endopeptidase enhancer 1, glial cell-line derived neurotrophic factor receptor α2, inter-alpha-trypsin inhibitor heavy chain 4, neural proliferation and differentiation control protein-1) revealed the ability to discriminate metastatic cases from controls. Combining a unique dataset of CSFs from pediatric CNS tumors with a novel enabling nanotechnology led us to identify CSF proteins potentially related to metastatic status.

Flow cytometric phenotype of rhabdomyosarcoma bone marrow metastatic cells and its implication in differential diagnosis with neuroblastoma.

BACKGROUND: The goal of this study was to develop a flow cytometric (FCM) method for assessing the presence of metastatic cells in bone marrow (BM) and peripheral blood (PB) obtained from rhabdomysarcoma (RMS) patients. Myogenin (Myf4), a specific molecular RMS marker, was also investigated in the same samples. Since neuroblastoma (NB) metastasizes to the BM, the potential application of cytometry in differential diagnosis was explored. PATIENTS AND METHODS: CD45, CD56, CD90 and CD57 antibodies were used in 7 paired BM and PB samples (from 7 RMS stage IV patients at presentation), 23 BM samples (from 13 RMS stage I and II patients at presentation), and ten paired BM and PB samples taken at presentation and five BM samples taken at recurrence from 13 NB stage 4 patients. RESULTS: All seven BM samples from RMS stage IV (but not those from patients with localized disease) showed both the CD45- CD56+ phenotype and the Myf4 transcript. Four cases also showed CD90 and two CD57 positivity. Neither the CD45- CD56+ phenotype, nor Myf4 were recorded in the BM and PB samples from patients with localized disease. All the NB BM samples (15/15) showed the CD45- CD56+ CD90+ phenotype and 10/15 also showed CD57 positivity. Only 3/10 blood samples from the NB patients revealed tumor cells. CONCLUSION: CD45, CD56, CD90 and CD57 antibodies can be used in FCM for marrow metastasis detection in both, RMS and NB patients.

Peripheral blood stem cell collection in pediatric patients: feasibility of leukapheresis under anesthesia in uncompliant small children with solid tumors.

Leukapheresis demands patient's compliance and adequate vascular accesses, which can require invasive methods in very small children whose treatment protocol includes hemopoietic stem cell collection for myeloablative chemotherapy and stem cell rescue. Since 1998, at the Istituto Nazionale Tumori of Milan, in selected uncompliant small children, the placement of peripheral vascular accesses and leukapheresis have been performed at the same time under general anesthesia. Peripheral venous cannulas were positioned for blood collection, while blood was returned through either peripheral cannulas or mono-lumen central catheters previously installed for chemotherapy. A continuous-flow cell separator was used for leukapheresis. Between 1998 and 2003, 47 children with solid tumors underwent anesthesia for a total of 54 leukaphereses. The patients' age ranged from 12.7 to 93 months (median 30.3) and their weight ranged from 7 to 20 kg (median 14.1). Neither metabolic nor anesthesiological complications were recorded. In 89% of cases, the CD 34(+) cell target was achieved at a single harvest; the median number of CD 34(+) cells was 10.8 x 10(6)/kg/leukapheresis (range 1-117) and the median collection efficiency was 63.4% (range 25-100.6). Leukapheresis under anesthesia is feasible and safe in very low-weight children whose compliance is lacking due to age and disease.

Molecular detection of dopamine decarboxylase expression by means of reverse transcriptase and polymerase chain reaction in bone marrow and peripheral blood: utility as a tumor marker for neuroblastoma.

A highly sensitive molecular method was used to evaluate the presence of dopamine decarboxylase (DDC) mRNA in the bone marrow and peripheral blood of patients with neuroblastoma (NB). DDC, like tyrosine hydroxylase (TH), is an enzyme involved in the catecholamine synthesis pathway and has recently been proposed as a specific marker of NB among pediatric malignancies. DDC transcript was detected in five of five NB cell lines, 10 of 10 NB primary tumors, 17 of 18 (94%) bone marrow samples, and 12 of 18 (66%) blood samples drawn at diagnosis in 18 patients affected by disseminated NB. In contrast, no PCR signal was found in 20 bone marrow samples obtained from patients with other malignancies or in eight of nine marrow and blood samples drawn from patients with localized NB (two stage 2 and seven stage 3). In addition, all marrow and blood samples obtained from NB patients at relapse revealed DDC mRNA. Furthermore, the percentage of DDC-positive samples was lower among the samples drawn from these patients during treatment. By comparison with conventional methods for disease evaluation, DDC transcript research can increase the sensitivity of NB cell detection in marrow and blood samples at diagnosis and during the treatment and follow-up of NB patients. These results suggest that finding DDC mRNA in NB patients could be a potential marker for minimal residual disease study.