Identification of genomic aberrations in hemangioblastoma by droplet digital PCR and SNP microarray highlights novel candidate genes and pathways for pathogenesis

Background: The genetic mechanisms underlying hemangioblastoma development are still largely unknown. We used high-resolution single nucleotide polymorphism microarrays and droplet digital PCR analysis to detect copy number variations (CNVs) in total of 45 hemangioblastoma tumors. Results: We identified 94 CNVs with a median of 18 CNVs per sample. The most frequently gained regions were on chromosomes 1 (p36.32) and 7 (p11.2). These regions contain the EGFR and PRDM16 genes. Recurrent losses were located at chromosome 12 (q24.13), which includes the gene PTPN11. Conclusions: Our findings provide the first high-resolution genome-wide view of chromosomal changes in hemangioblastoma and identify 23 candidate genes: EGFR, PRDM16, PTPN11, HOXD11, HOXD13, FLT3, PTCH, FGFR1, FOXP1, GPC3, HOXC13, HOXC11, MKL1, CHEK2, IRF4, GPHN, IKZF1, RB1, HOXA9, and micro RNA, such as hsa-mir-196a-2 for hemangioblastoma pathogenesis. Furthermore, our data implicate that cell proliferation and angiogenesis promoting pathways may be involved in the molecular pathogenesis of hemangioblastoma

Elevated NLR May Be a Feature of Pediatric Brain Cancer Patients

Pediatric brain tumors are the most common solid tumor type and the leading cause of cancer-related death in children. The immune system plays an important role in cancer pathogenesis and in the response to immunotherapy treatments. T lymphocytes are key elements for the response of the immune system to cancer cells and have been associated with prognosis of different cancers. Neutrophils on the other hand, which secrete pro-angiogenic and anti-apoptotic factors, enhance the ability of tumor cells to grow and develop into metastases. We conducted a retrospective study of 120 pediatric brain cancer patients and 171 elective pediatric patients hospitalized in Dana Children's Hospital and Sheba Medical Center. Data on age, sex, treatment, lymphocyte, neutrophil, and monocyte count were collected from routinely performed preoperative blood tests. Neutrophil-to-lymphocyte ratio (NLR), and the lymphocyte-to-monocyte ratio (LMR) were calculated and significance was determined by paired T test. p < 0.05 was considered as statistically significant. NLR was significantly higher in the pediatric brain cancer patients. The high NLR in pediatric brain cancer patients is the result of a combination of low lymphocytes and high neutrophils. Both of these factors can have a role in cancer development and propagation and also in response to therapy

The type II RAF inhibitor tovorafenib in relapsed/refractory pediatric low-grade glioma: the phase 2 FIREFLY-1 trial

BRAF genomic alterations are the most common oncogenic drivers in pediatric low-grade glioma (pLGG). Arm 1 (n = 77) of the ongoing phase 2 FIREFLY-1 (PNOC026) trial investigated the efficacy of the oral, selective, central nervous system-penetrant, type II RAF inhibitor tovorafenib (420 mg m$^{-}$$^{2}$ once weekly; 600 mg maximum) in patients with BRAF-altered, relapsed/refractory pLGG. Arm 2 (n = 60) is an extension cohort, which provided treatment access for patients with RAF-altered pLGG after arm 1 closure. Based on independent review, according to Response Assessment in Neuro-Oncology High-Grade Glioma (RANO-HGG) criteria, the overall response rate (ORR) of 67% met the arm 1 prespecified primary endpoint; median duration of response (DOR) was 16.6 months; and median time to response (TTR) was 3.0 months (secondary endpoints). Other select arm 1 secondary endpoints included ORR, DOR and TTR as assessed by Response Assessment in Pediatric Neuro-Oncology Low-Grade Glioma (RAPNO) criteria and safety (assessed in all treated patients and the primary endpoint for arm 2, n = 137). The ORR according to RAPNO criteria (including minor responses) was 51%; median DOR was 13.8 months; and median TTR was 5.3 months. The most common treatment-related adverse events (TRAEs) were hair color changes (76%), elevated creatine phosphokinase (56%) and anemia (49%). Grade ≥3 TRAEs occurred in 42% of patients. Nine (7%) patients had TRAEs leading to discontinuation of tovorafenib. These data indicate that tovorafenib could be an effective therapy for BRAF-altered, relapsed/refractory pLGG. ClinicalTrials.gov registration: NCT04775485

Malignant transformation of a conservatively managed incidental childhood cerebral mass lesion: controversy regarding management paradigm

BACKGROUND: Incidental findings on neuroimaging in the pediatric population are an emerging treatment challenge. Treatment options for these incidental childhood brain mass lesions, which radiologically may be assumed to be low-grade gliomas (LGG), vary, ranging from careful conservative `wait and scan` treatment to surgical biopsy, gross total resection, and upfront radiation and/or chemotherapy. As malignant transformation of LGG in children is extremely rare, some series advocate careful conservative management of these lesions; however, universal treatment protocols are not totally agreed upon. ILLUSTRATIVE CASE: We present the case of a 10-year-old boy with a fronto-basal incidental cerebral mass lesion, suspected to be a low-grade glial neoplasm. Initially, magnetic resonance imaging (MRI) was done to rule out a pathology causing his growth to be delayed. A treatment with growth hormone was initiated. After close clinical and radiological follow-up of this asymptomatic lesion for 6 years, a minimal growth of the lesion was seen, which we decided to continue following. After 7 years, a clear growth with new contrast enhancement was seen on routine MRI. At this point, the lesion was surgically resected. The diagnosis was, surprisingly, glioblastoma multiforme (WHO grade IV, BRAF V-600E mutation). DISCUSSION: Malignant transformation of LGGs in children is a very rare phenomenon. This is to our knowledge the first well-documented case describing malignant transformation of a suspected benign pediatric cerebral mass lesion, which did not undergo radiation, in a patient without a cancer predisposition syndrome (e.g., neurofibromatosis), with the transformation occurring after such a long follow-up period. The management of these lesions is still controversial. Unfortunately, radiological risk factors for malignant transformation of such lesions in the pediatric age group are lacking. CONCLUSION: Conservative treatment of incidental cerebral mass lesions in children seems a valid option. These lesions should probably be followed indefinitely, while carefully watching for changes in imaging characteristics