Retrospective Analysis of Imaging Characteristics of Tectal Gliomas.

BACKGROUND AND PURPOSE: Tectal gliomas (TGs) are rare tumors that involve critical locations in the brainstem, including the superior and inferior colliculi and the Sylvian aqueduct. The rarity of these tumors and the lack of large clinical studies have hindered adequate understanding of this disease. We sought to determine the association between imaging characteristics of TG and progression-free survival (PFS). MATERIALS AND METHODS: In this retrospective cohort study, impact of imaging characteristics (contrast enhancement, calcifications, cystic changes, presence of hydrocephalus) on survival was analyzed for 39 patients with TG. We used the Kaplan-Meier survival analysis method for determining the association between imaging characteristics and PFS. Progression-free survival was measured from time of diagnosis to radiographic or pathological disease progression during observation period. Progression was defined as more than 25% increase of the lesion in size, per response assessment in neuro-oncology, together with clinical deterioration and/or a need for intervention. Progression-free survival differences by various imaging characteristics were assessed using the log-rank test and univariable Cox proportional hazard regression. Because most of the studies in the current literature tend to overrepresent pediatric patients, we aimed to determine the association between TG tumors' imaging characteristics and PFS in both adult and pediatric patients. All statistical analyses were performed using STATA version 16.1 (Stata Corp, College Station, Tex). RESULTS: Of the 39 patients, radiographic tumor progression was observed in 15 cases (38.5%). Median PFS for 39 patients during observation was 21.8 years. Tectal gliomas that showed contrast enhancement initially or developed contrast enhancement during surveillance on magnetic resonance imaging had significantly lower PFS than those without (hazard ratio, 3.55; 95% confidence interval, 1.09-11.58; log-rank P value, 0.02). CONCLUSIONS: Analysis of this patient population showed that contrast-enhancing TGs should not be categorically defined as benign lesions. This subgroup of patients should be followed closely for signs of progression.

Contrast Enhancement Patterns in Pediatric Glioblastomas.

BACKGROUND AND PURPOSE: Brain tumors are the most common cause of cancer-related deaths among the pediatric population. Among these, pediatric glioblastomas (GBMs) comprise 2.9% of all central nervous system tumors and have a poor prognosis. The purpose of this study is to determine whether the imaging findings can be a prognostic factor for survival in children with GBMs. MATERIALS AND METHODS: The imaging studies and clinical data from 64 pediatric patients with pathology-proven GBMs were evaluated. Contrast enhancement patterns were classified into focal, ring-like, and diffuse, based on preoperative postcontrast T1-weighted magnetic resonance images. We used the Kaplan-Meier method and Cox proportional hazard regression to evaluate the prognostic value of imaging findings. RESULTS: Patients with ring-enhanced GBMs who underwent gross total resection or subtotal resection were found to have a significantly shorter progression-free survival ( P = 0.03) comparing with other enhancing and nonenhancing glioblastomas. CONCLUSIONS: In this study, we analyzed survival factors in children with pediatric glioblastomas. In the group of patients who underwent gross total resection or subtotal resection, those patients with focal-enhanced GBMs had significantly longer progression-free survival ( P = 0.03) than did those with other types of enhancing GBMs (diffuse and ring-like).

A Bayesian method for safety signal detection in ongoing blinded randomised controlled trials.

Sponsors have a responsibility to minimise risk to participants in clinical studies through safety monitoring. The FDA Final Rule for IND Safety Reporting requires routine aggregate safety evaluation, including in ongoing blinded studies. We are interested in estimating the probability that the true adverse event rate in the experimental arm exceeds that in the control arm. We developed a Bayesian approach that specifies an informative meta-analytic predictive prior on the event probability in the control arm and an uninformative prior on that in the experimental arm. We combined these priors with a mixture likelihood that considers each patient in the ongoing blinded study may belong to the experimental or control arm. This allowed us to estimate the quantity of interest without unblinding. We evaluated our method by simulation, pairing scenarios that differed only in whether a safety signal was present or missing, and quantifying the ability of our model to discriminate using signal detection theory. Our approach shows benefit. It detects safety signals more reliably with greater sample sizes and for common rather than rare events. Performance does not deteriorate markedly when historical studies exhibit heterogeneous hazards or non-constant hazards. Our method will allow us to monitor safety signals in ongoing blinded studies with the goal of earlier identification and risk mitigation. Our method could be adapted to use informative priors on both arms or predictive covariates where pertinent data exist. We stress that ongoing safety monitoring should involve a multi-disciplinary team where statistical methods are paired with medical judgement.

Clinical significance of FBXO17 gene expression in high-grade glioma.

BACKGROUND: High-grade gliomas (HGGs) exhibit marked heterogeneity in clinical behavior. The purpose of this study was to identify a novel biomarker that predicts patient outcome, which is helpful in HGG patient management. METHODS: We analyzed gene expression profiles of 833 HGG cases, representing the largest patient population ever reported. Using the data set from the Cancer Genome Atlas (TCGA) and random partitioning approach, we performed Cox proportional hazards model analysis to identify novel prognostic mRNAs in HGG. The predictive capability was further assessed via multivariate analysis and validated in 4 additional data sets. The Kaplan-Meier method was used to evaluate survival difference between dichotomic groups of patients. Correlation of gene expression and DNA methylation was evaluated via Student's t-test. RESULTS: Patients with elevated FBXO17 expression had a significantly shorter overall survival (OS) (P = 0.0011). After adjustment by IDH1 mutation, sex, and patient age, FBXO17 gene expression was significantly associated with OS (HR = 1.29, 95% CI =1.04-1.59, P = 0.018). In addition, FBXO17 expression can significantly distinguish patients by OS not only among patients who received temozolomide chemotherapy (HR 1.35, 95% CI =1.12-1.64, P = 0.002) but also among those who did not (HR = 1.48, 95% CI =1.20-1.82, P < 0.0001). The significant association of FBXO17 gene expression with OS was further validated in four external data sets. We further found that FBXO17 endogenous expression is significantly contributable from its promoter methylation. CONCLUSION: Epigenetically modulated FBXO17 has a potential as a stratification factor for clinical decision-making in HGG.

Dorsal column myelopathy after intrathecal chemotherapy for leukemia.

Intrathecal chemotherapy with methotrexate, a folate antagonist, is widely used to treat central nervous system malignancies. The mechanisms underlying methotrexate-induced neurotoxicity are unclear but may be related to increased homocysteine levels. Intrathecal methotrexate-induced myelopathy mimicking subacute combined degeneration, with normal B12 levels, has been documented. We examined treatment and magnetic resonance imaging (MRI) characteristics of 13 patients with leukemia who received intrathecal methotrexate and developed urinary and bowel incontinence, ascending motor weakness, and sensory loss with dorsal column hyperintensity on MRI between 2000 and 2016. Cerebrospinal fluid evaluation was negative for leukemia in all patients and positive for elevated protein in 12 patients. Seven of eight patients with available data had reduced serum folate, increased serum homocysteine, or both, implicating methotrexate as the cause of neurotoxicity. Autopsy of one patient revealed loss of myelinated axons in the posterior columns. These findings suggest that methotrexate neurotoxicity may be mediated by folate antagonism. Awareness and a high index of suspicion of these characteristic clinical and radiographic features in patients who develop myelopathy after intrathecal methotrexate may help to avoid additional neurotoxic therapy in such patients.

Impact of IDH1 mutation status on outcome in clinical trials for recurrent glioblastoma.

IDH1 mutated glioblastoma (GB) has a better prognosis than IDH1 wildtype GB. However, it remains unknown whether patients (pts) with IDH1 mutated GB have a higher 6-month progression free survival (PFS6) or radiographic response (RR) rate on clinical trials for recurrence. Retrospective review of GB pts at MDACC between 2006 and 2012 identified 330 patients in recurrent GB trials. 93 patients (28 %) had either PFS6 or a complete/partial RR per RANO criteria. 49/93 (53 %) patients with PFS6 or a complete/partial RR had tumor tissue for IDH1 testing. A matched cohort of 49 patients on recurrent GB clinical trials that failed to achieve PFS6 or RR (also with tissue for IDH1 testing) was identified for comparison. IDH1 status was obtained in 92/98 (94 %) patients of which 17 (18 %) had an IDH1 mutation. PFS6 was seen in 26/49 (53 %) patients. IDH status was unknown in two of these patients. 5/24 (21 %) were IDH1 mutated compared to 5/24 (21 %) of their matched cohort without PFS6. RR was found in 47/49 (94 %) patients. IDH status was unknown in four of these patients. IDH1 mutation was present in 7/43 (16 %) patients with RR compared to 10/43 (23 %) in the matched cohort without RR (p = 0.48). Median OS for trials at first recurrence was 9.8 months for IDH1 wildtype GB vs. 19.32 months for IDH1 mutated GB (p = 0.14). IDH1 mutation status was not predictive of PFS6 or RR in recurrent GB trials for this data set. However, further examination in larger randomized prospective studies is needed.

Overexpression and constitutive nuclear localization of cohesin protease Separase protein correlates with high incidence of relapse and reduced overall survival in glioblastoma multiforme.

Separase, an enzyme that cleaves the chromosomal cohesin during mitosis, is overexpressed in a wide range of human epithelial cancers of breast, bone and prostate (Meyer et al., Clin Cancer Res 15(8):2703-2710, 2009). Overexpression of Separase in animal models results in aneuploidy and tumorigenesis. We have examined the expression and localization of Separase protein in adult and pediatric glioblastoma and normal brain specimens. Immunofluorescence microscopy and Western blot analysis showed significant overexpression of Separase in all adult and a subset of pediatric glioblastoma cells. Tumor status and patient survival strongly correlate with the mislocalization of Separase into the nucleus throughout all stages of the cell cycle. Unlike exclusively nuclear localization in mitotic control cells, glioblastoma samples have a significantly higher number of resting (interphase) cells with strong nuclear Separase staining. Additionally, patient survival analysis demonstrated a strong correlation between overexpression of Separase protein in adult glioblastoma and a high incidence of relapse and reduced overall survival. These results further strengthen our hypothesis that Separase is an oncogene whose overexpression induces tumorigenesis, and indicate that Separase overexpression and aberrant nuclear localization are common in many tumor types and may predict outcome in some human malignancies.

Phospho-histone H3 (pHH3) immuno-reactivity as a prognostic marker in non-functioning pituitary adenomas.

Nonfunctioning pituitary adenomas (NFPA) are typically benign neoplasms that can cause significant morbidity through local mass effects. MIB-1/Ki-67 and p53 immuno-reactivity are used to predict aggressive behavior but have known limitations. No marker to date is widely used to reliably predict tumor progression. Phospho-histone H3 (pHH3) is a protein phosphorylated during chromatin condensation in mitosis, and thus anti-pHH3 immunocytochemistry is able to assess mitotic activity. Study objectives were to determine the relationship among pHH3, MIB-1/Ki-67, and p53 in NFPA, and to evaluate the relationship between these indices and time to progression (TTP). Seventy-six patients with NFPA operated on by a single neurosurgeon at University of Texas M. D. Anderson Cancer Center from 1992 to 2006 were identified from a database and met all criteria for inclusion in this clinicopathology study. PHH3, MIB-1/Ki-67, and p53 immuno-reactivity was evaluated in each case. Retrospective review was used to determine TTP. With 282 person-years of follow-up, 19 progression events were observed. A correlation was found between MIB-1/Ki-67 and p53 immuno-reactivity (r = 0.25, p = 0.031). PHH3 did not correlate with either. When markers were dichotomized at the median, only MIB-1/Ki-67 correlated with TPP (log rank p = 0.018). Rank correlation analysis confirmed a significant inverse correlation between both MIB-1/Ki-67 (Dxy = -0.33, p = 0.036) and p53 (Dxy = -0.40, 0.016) immuno-reactivity and TTP. Our results support previous data suggesting that MIB-1/Ki-67 and p53 have clinical utility as prognostic markers for tumor progression. PHH3 did not prove to be associated with TTP in this retrospective study limited by few progression events.

Clinical and survival characteristics of primary and secondary gliosarcoma patients.

PURPOSE: Gliosarcoma (GS) is classified by the World Health Organization as a subtype of glioblastoma with sarcomatous features. GS have a propensity to metastasize, as opposed to other gliomas, with lower 5-year survival rates than GBM patients. In this study, we identified differences in survival between patients with primary and secondary GS. METHODS: We retrospectively identified patients who presented at the MD Anderson Cancer Center with a pathology-confirmed diagnosis of GS. We defined overall survival (OS) from the date of pathological diagnosis of primary GS (from sarcomatous change for secondary GS). We defined progression-free survival (PFS) from the date of GS chemoradiation completion to radiographic disease progression. We used Kaplan-Meier survival estimates and the log-rank test to compare OS and PFS between primary and secondary GS. We used univariable Cox proportional hazard regression to assess differences in OS & PFS by various characteristics. RESULTS: We identified 94 GS patients; 70 had primary disease and 24 secondary. Molecular analysis of GS tumor samples revealed that 47.1% were GFAP positive, 38.5% S-100 positive, and 83.7% reticulin-positive. Among the tested samples, 3.8% had IDH and 73.1% had TP53 mutations. The median OS for all patients was 16.8 months. Median OS from the pathological diagnosis of GS was 17.3 months for primary and 10.2 months for secondary GS. Median OS for secondary GS was 28.9 months from initial diagnosis of the primary neoplasm. CONCLUSIONS: Our study is the largest single institution evaluation of GS and provides insight into patterns of survival for GS.

Retinoic acid induces REST degradation and neuronal differentiation by modulating the expression of SCF(ß-TRCP) in neuroblastoma cells.

BACKGROUND: The repressor element-1 silencing transcription factor (REST) is a repressor of neuronal genes. Its expression is associated with poor neuronal differentiation in many neuroblastoma patient samples and cell lines. Because retinoic acid promotes neuronal differentiation, the authors postulated that it involves modulation of REST expression. METHODS: The expression of REST and of an S-phase kinase-associated protein 1/cullin 1/F-box (SCF) protein complex that contains the F-box protein ß-transducin repeat-containing protein (ß-TRCP) (SCF(ß-TRCP) ) in neuroblastoma tumor samples and cell lines was analyzed by immunofluorescence and Western blot analysis. SK-N-SH and SK-N-AS cells were treated with retinoic acid and MG-132 to measure proteasomal degradation of REST by Western blot and quantitative real-time polymerase chain reaction analyses. Immunoprecipitation and coimmunoprecipitation assays were done in SK-N-AS cells that were transfected either with a control plasmid or with an enhanced green fluorescent protein-SCF(ß-TRCP) -expressing plasmid. RESULTS: Several neuroblastoma patient samples and cell lines displayed elevated REST expression. Although, REST transcription increased upon retinoic acid treatment in SK-N-SH and SK-N-AS cells, REST protein levels declined, concomitant with the induction of neuronal differentiation, in SK-N-SH cells but not in SK-N-AS cells. MG-132 treatment countered the retinoic acid-mediated decline in REST protein. SCF(ß-TRCP) , a known REST-specific E3-ligase, was poorly expressed in many neuroblastoma samples, and its expression increased upon retinoic acid treatment in SK-N-SH cells but declined in SK-N-AS cells. Ectopic expression of SCF(ß-TRCP) in SK-N-AS cells promoted REST ubiquitination and degradation and neuronal differentiation. CONCLUSIONS: The current results indicated that elevated transcription of REST compounded by its impaired degradation by SCF(ß-TRCP) may contribute to the failure of these tumors to differentiate in response to retinoic acid.

Hearing Health Care Belongs to Primary Care.

Like many areas of health care, hearing loss is best managed when hearing professionals collaborate closely with physicians. Primary care physicians (PCPs) are uniquely suited to manage hearing loss because 1) patients trust their PCP; 2) PCPs have insight into the overall health and well-being of their patients; and 3) the PCP workforce is large enough to make a meaningful impact. Accountable care organizations, clinically integrated networks, and patient-centered medical homes are perfectly suited to be a positive force in the hearing health of their patients.

Reactivation of death receptor 4 (DR4) expression sensitizes medulloblastoma cell lines to TRAIL.

OBJECT: Apoptosis, a key cellular response to therapeutic agents is often inactivated in tumor cells. In this study, we evaluated the expression of the tumor necrosis family of death receptors, DR4 and DR5, in medulloblastoma tumor samples and cell lines to determine if epigenetic modulation of gene expression could sensitize tumor cell lines to TRAIL-mediated apoptosis. METHODS: Human medulloblastoma samples and cell lines were analyzed for DR4 and DR5 expression by quantitative PCR and immunofluorescence assays. Cell lines with downregulated expression of one or both genes were treated with the histone deacetylase inhibitor, MS-275, and the expression of DR4 and DR5 measured by quantitative PCR, Western blotting, flow cytometry and chromatin immunoprecipitation assays. Induction of apoptosis in the presence of MS-275 was evaluated by TUNEL assay and its ability to augment TRAIL-mediated cytotoxicity was determined by MTT assays, Western blotting and flow cytometry. RESULTS: Compared to normal cerebellum, DR4, but not DR5 expression was consistently downregulated in medulloblastoma tumor samples and in Daoy and D283 cell lines. Interestingly, MS-275 decreased cell growth and induced apoptosis in Daoy and D283 cells. In Daoy cells, this coincided with increased histone H3 and H4 acetylation at the DR4 promoter and enhanced DR4 gene and protein expression as well as elevated Caspase-8 activity. The involvement of DR4 in the cellular response to MS-275 was further confirmed by the observation that knockdown of DR4 and FADD abrogated apoptosis. Further, addition of TRAIL to MS-275 treated cells resulted in an enhancement of apoptosis, suggesting that the upregulated death receptors were functional. CONCLUSION: Our study provides an understanding of the role of DR4 in apoptosis of medulloblastoma cell lines and suggests a potential contribution of aberrant histone deacetylation to the resistance of medulloblastoma cells to therapeutic death.

Imaging and spectroscopic findings in meningioangiomatosis.

Meningioangiomatosis (MA) is an uncommon brain tumor. The role of imaging techniques is underscored in cases where the tumor location makes resection (or even biopsy) dangerous. We report the case of a child with an MA tumor located deep in the right sylvian fissure. A computed tomography (CT) scan showed calcifications in a highly vascular lesion with surrounding edema. Magnetic resonance spectroscopy (MRS) showed a distinct choline (Cho) peak, which usually suggests a proliferating tumor. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed the lesion lacked hypermetabolic features. These radiological features should put MA in the differential diagnosis.

The 2007 WHO classification of tumors of the nervous system: controversies in surgical neuropathology.

Controversy surrounds the recent 2007 WHO Classification of Tumours of the Nervous System. A number of nosologic issues remain to be resolved, some a reflection of conceptual disagreement, others the result of inadequate data to permit their definitive resolution. Among these and discussed herein are (i) the nosologic place of highly anaplastic oligoastrocytic tumors, (ii) the forms and significance of microvascular changes in high-grade gliomas, (iii) the makeup of the glioneuronal tumors category, (iv) the subclassification of pineal parenchymal tumors of intermediate type, and (v) the classification of principle forms of mesenchymal neoplasms, specifically hemangiopericytoma and solitary fibrous tumor. These issues and others are the substance of this and an upcoming companion article.

PD-L1 expression and prognostic impact in glioblastoma.

BACKGROUND: Therapeutic targeting of the immune checkpoints cytotoxic T-lymphocyte-associated molecule-4 (CTLA-4) and PD-1/PD-L1 has demonstrated tumor regression in clinical trials, and phase 2 trials are ongoing in glioblastoma (GBM). Previous reports have suggested that responses are more frequent in patients with tumors that express PD-L1; however, this has been disputed. At issue is the validation of PD-L1 biomarker assays and prognostic impact. METHODS: Using immunohistochemical analysis, we measured the incidence of PD-L1 expression in 94 patients with GBM. We categorized our results according to the total number of PD-L1-expressing cells within the GBMs and then validated this finding in ex vivo GBM flow cytometry with further analysis of the T cell populations. We then evaluated the association between PD-L1 expression and median survival time using the protein expression datasets and mRNA from The Cancer Genome Atlas. RESULTS: The median percentage of PD-L1-expressing cells in GBM by cell surface staining is 2.77% (range: 0%-86.6%; n = 92), which is similar to the percentage found by ex vivo flow cytometry. The majority of GBM patients (61%) had tumors with at least 1% or more PD-L1-positive cells, and 38% had at least 5% or greater PD-L1 expression. PD-L1 is commonly expressed on the GBM-infiltrating T cells. Expression of both PD-L1 and PD-1 are negative prognosticators for GBM outcome. CONCLUSIONS: The incidence of PD-L1 expression in GBM patients is frequent but is confined to a minority subpopulation, similar to other malignancies that have been profiled for PD-L1 expression. Higher expression of PD-L1 is correlated with worse outcome.

MiR-138 exerts anti-glioma efficacy by targeting immune checkpoints.

BACKGROUND: Antibody therapeutic targeting of the immune checkpoints cytotoxic T-lymphocyte-associated molecule 4 (CTLA-4) and programmed cell death 1 (PD-1) has demonstrated marked tumor regression in clinical trials. MicroRNAs (miRNAs) can modulate multiple gene transcripts including possibly more than one immune checkpoint and could be exploited as immune therapeutics. METHODS: Using online miRNA targeting prediction algorithms, we searched for miRNAs that were predicted to target both PD-1 and CTLA-4. MiR-138 emerged as a leading candidate. The effects of miR-138 on CTLA-4 and PD-1 expression and function in T cells were determined and the therapeutic effect of intravenous administration of miR-138 was investigated in both immune-competent and -incompetent murine models of GL261 glioma. RESULTS: Target binding algorithms predicted that miR-138 could bind the 3' untranslated regions of CTLA-4 and PD-1, which was confirmed with luciferase expression assays. Transfection of human CD4+ T cells with miR-138 suppressed expression of CTLA-4, PD-1, and Forkhead box protein 3 (FoxP3) in transfected human CD4+ T cells. In vivo miR-138 treatment of GL261 gliomas in immune-competent mice demonstrated marked tumor regression, a 43% increase in median survival time (P = .011), and an associated decrease in intratumoral FoxP3+ regulatory T cells, CTLA-4, and PD-1 expression. This treatment effect was lost in nude immune-incompetent mice and with depletion of CD4+ or CD8+ T cells, and miR-138 had no suppressive effect on glioma cells when treated directly at physiological in vivo doses. CONCLUSIONS: MiR-138 exerts anti-glioma efficacy by targeting immune checkpoints which may have rapid translational potential as a novel immunotherapeutic agent.

Primary extradural meningioma presenting as a neck mass: Case report and review of the literature.

BACKGROUND: Primary extradural meningiomas (PEMs) are rare, particularly those involving the paraspinal cervical area, so little is known about them. We identified a new case and compared it with 10 previous cases, addressed the diagnostic challenges, and highlighted the clinical and pathologic characteristics. METHODS: We conducted a case report and literature review of PEM cases reported since 1976. RESULTS: A 59-year-old man presented with right neck stiffness and discomfort that was present over the last several months, which is consistent with other cases. CT scan and MRI revealed a paraspinal cervical mass. Fine-needle aspiration (FNA) and core biopsy revealed spindle cells with whorling consistent with meningioma. The patient underwent complete en bloc resection of the tumor. The PEM was histologically benign. CONCLUSION: Cervical PEMs should be considered in the differential diagnosis of a deep neck mass. These tumors are typically benign and are surgically resected.

Clinical and prognostic features of adult patients with gangliogliomas.

BACKGROUND: Gangliogliomas (GGs) represent <1% of primary brain tumors in adults. Little is known regarding prognostic features, clinical characteristics, or the impact of treatment on patient outcomes. METHODS: Our neuro-oncology longitudinal database was screened for patients with GG from 1992 to 2012. Sixty-seven patients (age >18 y) were identified. RESULTS: Sixty-two patients presented with low-grade GG and 5 with anaplastic GG. The median age at diagnosis was 29 years. With a median follow-up of 4.7 years after the initial diagnosis, 23 patients had progressive disease. Range of time to progression was 0.2-20 years. Nine patients with low-grade GG progressed to a malignant tumor. The median overall survival (OS) for all patients was not reached. The 2-, 5-, and 10-year OS for patients with low-grade GG were 100%, 88% (95% confidence interval [CI]: 73%, 95%), and 84% (95% CI: 67%, 93%), respectively. Factors identified by univariate analysis that were significantly associated with OS were age, KPS, extent of resection (EOR), and grade. Factors on univariate analysis that were significantly associated with progression-free survival were grade and EOR. On multicovariate Cox regression, lower tumor grade and younger age were significant factors for longer OS. EOR is a significant factor for progression-free survival. CONCLUSIONS: While GG has excellent prognosis, malignant histologic grade, older age, and diagnosis with biopsy could indicate worse prognosis. The late nature and high rate of progression emphasize the importance of long-term follow-up. The role of chemotherapy and radiation therapy for incompletely resected low-grade GG remains unclear.

Survival prediction in patients with glioblastoma multiforme by human telomerase genetic variation.

PURPOSE: Glioblastoma multiforme (GBM) is the most common and aggressive glioma with the poorest survival. Use of biomarkers for screening patients with GBM may be used to modify treatments and improve outcomes. The level of human telomerase (hTERT) expression is an independent predictor of outcome of many cancers, and a functional variant of hTERT MNS16A (shorter tandem repeats or short [S] allele) is associated with increased hTERT mRNA expression. We investigated whether hTERT MNS16A variant genotype predicted survival in GBM patients. PATIENTS AND METHODS: We genotyped hTERT MNS16A in 299 GBM patients using polymerase chain reaction and determined hTERT genotype by classifying the DNA band of 243 or 272 base pairs (bp) as S allele and 302 or 333 bp as long (L) allele. We compared overall survival using Kaplan-Meier estimates and equality of survival distributions using the log-rank test, and we computed univariate and multivariate Cox proportional hazards models to estimate the effects of selected variables. RESULTS: Overall survival differed significantly by hTERT MNS16A genotype, with median survivals of 25.1, 14.7, and 14.6 months for the SS, SL, and LL genotypes, respectively. Compared with the SS genotype, the hazard ratios for the SL and LL genotypes were 1.69 and 1.87, respectively, after adjustment for other factors. Multivariate Cox regression analysis showed an independent statistically significant association between the hTERT MNS16A variant genotype and outcome. CONCLUSION: A functional hTERT MNS16A genotype is a potential biomarker for assessment of survival outcome of GBM. Larger studies are needed to verify these findings.