IL16 and factor V gene variations are associated with asparaginase-related thrombosis in childhood acute lymphoblastic leukemia patients.

Aim: We previously conducted exome-wide association study in acute lymphoblastic leukemia patients and identified association of five SNPs with asparaginase-related thrombosis. Here we aimed to replicate these findings in an independent patient cohort and through analyses in vitro. Patients & methods: SNPs located in IL16, MYBBP1A, PKD2L1, RIN3 and MPEG1 genes were analyzed in patients receiving Dana-Farber Cancer Institute acute lymphoblastic leukemia treatment protocols 05-001 and 11-001. Thrombophilia-related variations were also analysed. Results: IL16 rs11556218 conferred higher risk of thrombosis and higher in vitro sensitivity to asparaginase. The association was modulated by the treatment protocol, risk group and immunophenotype. A crosstalk between factor V Leiden, non-O blood groups and higher risk of thrombosis was also seen. Conclusion: IL16 and factor V Leiden variations are implicated in asparaginase-related thrombosis.

This study looked at how certain genetic variations are related to a higher risk of blood clots in children with a type of cancer called acute lymphoblastic leukemia who are receiving a certain treatment (asparaginase). The study found that one specific genetic variation (IL16 rs11556218) was linked to a higher risk of blood clots (thrombosis), and that this risk was influenced by disease and treatment features. The study also found that a certain genetic variation (factor V Leiden), which makes blood more likely to clot, and blood type (non-O) were linked to a higher risk of thrombosis. The conclusion of this study is that genetic variations may play a role in blood clots in children with acute lymphoblastic leukemia receiving asparaginase, and if further confirmed, these variations can serve to advance personalized treatment strategies.

Correction to: Efficacy of Dabrafenib for three children with brainstem BRAFV600E positive ganglioglioma.

In the original article, the author names were published incorrectly. The names are correct in this publication.

Trametinib for progressive pediatric low-grade gliomas.

INTRODUCTION: Pediatric pilocytic astrocytomas (PAs) are low grade gliomas and the most common brain tumors in children. They often represent a therapeutic challenge when incompletely resected as they can recur and progress despite the use of several lines of chemotherapeutic agents or even radiation therapy. Genetic alterations leading to activation of the mitogen-activated-protein-kinase pathway are a hallmark of this disease and offer an interesting therapeutic alternative through the use of targeted inhibitors. METHODS: Here, we describe six children with sporadic PA who were treated with trametinib, a MEK inhibitor, following progression under conventional therapies. Retrospective chart review was performed. RESULTS: The median age at diagnosis was 2.3 years (y) old [range 11 months (m)-8.5 y old]. KIAA1549-BRAF fusion was identified in five cases, and hotspot FGFR1/NF1/PTPN11 mutations in one. All patients received at least one previous line of chemotherapy (range 1-4). The median time on treatment was 11 m (range 4-20). Overall, we observed two partial responses and three minor responses as best response; three of these patients are still on therapy. Treatment was discontinued in the patient with progressive disease. The most frequent toxicities were minor to moderately severe skin rash and gastro-intestinal symptoms. Two patients had dose reduction due to skin toxicity. Quality of life was excellent with decreased hospital visits and a close to normal life. CONCLUSION: Trametinib appears to be a suitable option for refractory pediatric low-grade glioma and warrants further investigations in case of progression.

Neurotrophin receptors expression and JNK pathway activation in human astrocytomas.

BACKGROUND: Neurotrophins are growth factors that regulate cell growth, differentiation and apoptosis in the nervous system. Their diverse actions are mediated through two different transmembrane - receptor signaling systems: Trk receptor tyrosine kinases (TrkA, TrkB, TrkC) and p75NTR neurotrophin receptor. Trk receptors promote cell survival and differentiation while p75NTR induces, in most cases, the activity of JNK-p53-Bax apoptosis pathway or suppresses intracellular survival signaling cascades. Robust Trk activation blocks p75NTR -induced apoptosis by suppressing the JNK-p53-Bax pathway. The aim of this exploratory study was to investigate the expression levels of neurotrophin receptors, Trks and p75NTR, and the activation of JNK pathway in human astrocytomas and in adjacent non-neoplastic brain tissue. METHODS: Formalin-fixed paraffin-embedded serial sections from 33 supratentorial astrocytomas (5 diffuse fibrillary astrocytomas, WHO grade II; 6 anaplastic astrocytomas, WHO grade III; 22 glioblastomas multiforme, WHO grade IV) were immunostained following microwave pretreatment. Polyclonal antibodies against TrkA, TrkB, TrkC and monoclonal antibodies against p75NTR and phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were used. The labeling index (LI), defined as the percentage of positive (labeled) cells out of the total number of tumor cells counted, was determined. RESULTS: Moderate to strong, granular cytoplasmic immunoreactivity for TrkA, TrkB and TrkC receptors was detected in greater than or equal to 10% of tumor cells in the majority of tumors independently of grade; on the contrary, p75NTR receptor expression was found in a small percentage of tumor cells (approximately 1%) in some tumors. The endothelium of tumor capillaries showed conspicuous immunoreactivity for TrkB receptor. Trk immunoreactivity seemed to be localized in some neurons and astrocytes in non-neoplastic tissue. Phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were significantly co-expressed in a tumor grade-dependent manner (p < 0.05). Interestingly, a statistically significant (p < 0.05) reverse relationship between Trk receptors LIs and pc-Jun/pJNK LIs was noted in some glioblastomas multiforme. CONCLUSION: In the context of astrocytomas, Trk receptors (TrkA, TrkB, TrkC) expression may promote tumor growth independently of grade. Furthermore, activation of JNK pathway may contribute to progression towards malignancy. Considering the fact that regional tumor heterogeneity may be a limiting factor for immunohistochemical studies, the significance of the reverse relationship between Trk receptors and pc-Jun/pJNK LIs with respect to biological behavior of human astrocytomas requires further evaluation.

Expression of p75NTR and Trk neurotrophin receptors in the enteric nervous system of human adults.

Recent evidence suggests that the expression of p75NTR and Trk neurotrophin receptors is essential for neuronal survival, not only during development, but also in adulthood. The aim of the present study was to investigate the cell localization and distribution of p75NTR and Trk receptors in the normal adult human enteric nervous system (ENS) using double-label immunohistochemistry. Immunoreactivity for p75NTR was observed in a few neurons, whereas Trk immunoreactivity was present in a higher percentage of neurons. Strong expression of both types of neurotrophin receptors was found in the enteric glia. In addition, Trk immunoreactivity was localized to nerve endings in the lamina propria, muscularis mucosa and along or between circular and longitudinal smooth muscle layers, as well as to the enteric epithelium. Furthermore, polynuclear cells, mast cells and folliculoreticular cells in the germinal layer of lymph nodes displayed p75NTR and/or Trk immunopositivity. Expression of neurotrophin receptors in an inflammatory tissue sample was much more intense compared with that of normal tissue samples. These results suggest that neurotrophin receptors, through interactions with neurotrophins, may play a critical role in functional integrity of the ENS during adulthood.