SUMMARY Despite extensive study, few therapeutic targets have been identified for glioblastoma (GBM). Here we show that patient derived glioma sphere cultures (GSCs) that resemble either the proneural (PN) or mesenchymal (MES) transcriptomal subtypes differ significantly in their biological characteristics. Moreover, we found that a subset of the PN GSCs undergo differentiation to a MES state in a TNFα/NF-κB dependent manner with an associated enrichment of CD44 subpopulations and radio-resistant phenotypes. We present data to suggest that the tumor microenvironment cell types such as macrophages/microglia may play an integral role in this process. We further show that the MES signature, CD44 expression, and NF-κB activation correlate with poor radiation response and shorter survival in patients with GBM.

The prognostic impact of TERT mutations has been controversial in IDH-wild tumors, particularly in glioblastomas (GBM). The controversy may be attributable to presence of potential confounding factors such as MGMT methylation status or patients’ treatment. This study aimed to evaluate the impact of TERT status on patient outcome in association with various factors in a large series of adult diffuse gliomas. We analyzed a total of 951 adult diffuse gliomas from two cohorts (Cohort 1, n = 758; Cohort 2, n = 193) for IDH1/2, 1p/19q, and TERT promoter status. The combined IDH/TERT classification divided Cohort 1 into four molecular groups with distinct outcomes. The overall survival (OS) was the shortest in IDH wild-type/TERT mutated groups, which mostly consisted of GBMs (P < 0.0001). To investigate the association between TERT mutations and MGMT methylation on survival of patients with GBM, samples from a combined cohort of 453 IDH-wild-type GBM cases treated with radiation and temozolomide were analyzed. A multivariate Cox regression model revealed that the interaction between TERT and MGMT was significant for OS (P = 0.0064). Compared with TERT mutant-MGMT unmethylated GBMs, the hazard ratio (HR) for OS incorporating the interaction was the lowest in the TERT mutant-MGMT methylated GBM (HR, 0.266), followed by the TERT wild-type-MGMT methylated (HR, 0.317) and the TERT wild-type-MGMT unmethylated GBMs (HR, 0.542). Thus, patients with TERT mutant-MGMT unmethylated GBM have the poorest prognosis. Our findings suggest that a combination of IDH, TERT, and MGMT refines the classification of grade II-IV diffuse gliomas.Electronic supplementary materialThe online version of this article (doi:10.1186/s40478-016-0351-2) contains supplementary material, which is available to authorized users.

The RET proto-oncogene is responsible for the development of several human inherited and non-inherited diseases. Germline point mutations were identified in multiple endocrine neoplasia types 2A and 2B, and familial medullary thyroid carcinoma. More than 10 rearranged forms of RET, referred to as RET/PTC 1-9, ELKS/RET and RFP/RET, have been cloned from sporadic and radiation-associated papillary thyroid carcinomas. These mutations induced oncogenic activation of RET tyrosine kinase by different mechanisms. I n 1985, the RET (REarranged during transfection) gene was identified as a novel oncogene activated by DNA rearrangement.(1) The resulting chimeric oncogene encoded a fusion protein, consisting of an amino-terminal half with a putative zinc finger motif, and a carboxyl-terminal half with a tyrosine kinase domain.(2) This fusion resulted from recombination between two unlinked human DNA segments, which occurred during the transfection process.The name RET (RET proto-oncogene) has been retained to designate the gene coding for the tyrosine kinase.(3) The RET proto-oncogene encodes a receptor tyrosine kinase with four cadherin-related motifs and a cysteine-rich region in the extracellular domain, and its ligands are glial cell line-derived neurotrophic factor (GDNF) and related molecules, including neurturin (NRTN), artemin (ARTN) and persephin (PSPN). RET activation by these neurotrophic factors is mediated through a unique multicomponent receptor system, consisting of glycosylphosphatidylinositol-anchored coreceptor (GFRα1-4) as a ligandbinding component and RET tyrosine kinase as a signaling component.(4 -6) Gene knock-out studies have revealed that GDNF/RET signal transduction is essential for the development of the kidney and the enteric nervous system. (7)(8)(9)(10) RET mutations are responsible for the development of several human diseases, including multiple endocrine neoplasia 2A and 2B (MEN 2A and MEN 2B), familial medullary thyroid carcinoma (FMTC), papillary thyroid carcinoma (PTC) and Hirschsprung's disease (HSCR).(11) MEN 2A and MEN 2B share the clinical features of medullary thyroid carcinoma (MTC) and pheochromocytoma, and FMTC is characterized by MTC alone. MEN 2A, MEN 2B and FMTC have been identified to be caused by gain-of-function germline mutations of RET, but somatic rearrangements of RET also lead to intrinsic tyrosine kinase activation in sporadic and radiation-associated PTC. In contrast, loss-of-function mutations of RET are responsible for the development of HSCR, which is a congenital malformation associated with the absence of enteric neurons. (11) Recently, useful therapeutic options for the treatment of neoplastic diseases have been developed, including the use of tyrosine kinase inhibitors, monoclonal antibodies or gene therapy. RET has also emerged as a potent target in some preclinical approaches to the treatment of RET-associated cancer. This artile discusses the mechanisms involved in oncogenic RET signaling and the potential of RET as a therapeutic target. Activation mechanis...

Molecular biological characterization of tumors has become a pivotal procedure for glioma patient care. The aim of this study is to build conventional MRI-based radiomics model to predict genetic alterations within grade II/III gliomas attempting to implement lesion location information in the model to improve diagnostic accuracy. One-hundred and ninety-nine grade II/III gliomas patients were enrolled. Three molecular subtypes were identified: IDH1/2-mutant, IDH1/2-mutant with TERT promoter mutation, and IDH-wild type. A total of 109 radiomics features from 169 MRI datasets and location information from 199 datasets were extracted. Prediction modeling for genetic alteration was trained via LASSO regression for 111 datasets and validated by the remaining 58 datasets. IDH mutation was detected with an accuracy of 0.82 for the training set and 0.83 for the validation set without lesion location information. Diagnostic accuracy improved to 0.85 for the training set and 0.87 for the validation set when lesion location information was implemented. Diagnostic accuracy for predicting 3 molecular subtypes of grade II/III gliomas was 0.74 for the training set and 0.56 for the validation set with lesion location information implemented. Conventional MRI-based radiomics is one of the most promising strategies that may lead to a non-invasive diagnostic technique for molecular characterization of grade II/III gliomas.

Phosphatase of regenerating liver (PRL)-3, encoding a 22-kD low molecular weight tyrosine phosphatase, has been reported to be associated with metastasis of colorectal carcinoma. We assessed the levels of PRL-3 mRNA expression to know whether its up-regulation was involved in progression and metastasis of gastric carcinoma. Levels of PRL-3 expression in 94 human gastric adenocarcinomas and 54 matched lymph node metastases were detected by in situ hybridization and compared with clinicopathological characteristics including prognosis. High PRL-3 expression was detected in 36.2% of primary gastric carcinoma (with nodal metastasis, 55.6%; without nodal metastasis, 10%; P < 0.001) and in 74.1% of lymph node metastases. The incidence of high PRL-3 expression in lymph node metastasis was significantly higher than in primary tumors (P < 0.044). Moreover, high expression of PRL-3 was closely associated with tumor size, lymphatic invasion, venous invasion, extent of lymph node metastasis, and tumor stage. These results suggest that high PRL-3 expression may participate in the progression and metastasis of gastric carcinoma. PRL-3 might be a novel molecular marker for aggressive gastric cancer.