Roy Dudley

Immune Checkpoint Inhibition for Hypermutant Glioblastoma Multiforme Resulting From Germline Biallelic Mismatch Repair Deficiency

PURPOSE Recurrent glioblastoma multiforme (GBM) is incurable with current therapies. Biallelic mismatch repair deficiency (bMMRD) is a highly penetrant childhood cancer syndrome often resulting in GBM characterized by a high mutational burden. Evidence suggests that high mutation and neoantigen loads are associated with response to immune checkpoint inhibition. PATIENTS AND METHODS We performed exome sequencing and neoantigen prediction on 37 bMMRD cancers and compared them with childhood and adult brain neoplasms. Neoantigen prediction bMMRD GBM was compared with responsive adult cancers from multiple tissues. Two siblings with recurrent multifocal bMMRD GBM were treated with the immune checkpoint inhibitor nivolumab. RESULTS All malignant tumors (n = 32) were hypermutant. Although bMMRD brain tumors had the highest mutational load because of secondary polymerase mutations (mean, 17,740 ± standard deviation, 7,703), all other high-grade tumors were hypermutant (mean, 1,589 ± standard deviation, 1,043), similar to other cancers that responded favorably to immune checkpoint inhibitors. bMMRD GBM had a significantly higher mutational load than sporadic pediatric and adult gliomas and all other brain tumors (P < .001). bMMRD GBM harbored mean neoantigen loads seven to 16 times higher than those in immunoresponsive melanomas, lung cancers, or microsatellite-unstable GI cancers (P < .001). On the basis of these preclinical data, we treated two bMMRD siblings with recurrent multifocal GBM with the anti-programmed death-1 inhibitor nivolumab, which resulted in clinically significant responses and a profound radiologic response. CONCLUSION This report of initial and durable responses of recurrent GBM to immune checkpoint inhibition may have implications for GBM in general and other hypermutant cancers arising from primary (genetic predisposition) or secondary MMRD.

Dystrophin-deficient cardiomyocytes are abnormally vulnerable to mechanical stress-induced contractile failure and injury

Although absence of the cytoskeletal protein dystrophin leads to dilated cardiomyopathy in humans, the functional role of dystrophin in cardiac muscle remains undefined. We have addressed the hypothesis that dystrophin could help protect the heart against injury and contractile dysfunction induced by mechanical stress. In normal and dystrophin‐deficient (mdx) mice, cardiac mechanical stress was first manipulated ex vivo in a perfused working heart preparation. Despite an afterload level in the normal physiologic range, ex vivo perfused mdx hearts developed severe contractile dysfunction and nonischemic tissue damage, as is shown by excessive LDH release without a rise in coronary lactate. Injury to dystrophin‐deficient hearts was significantly correlated with cardiac work, and reducing the afterload level improved contractility and prevented injury in mdx hearts studied ex vivo. The response to mechanical stress in vivo was also assessed by using the vital dye Evans blue, which penetrates into cardiomyocytes with a disrupted sarcolemma. In the mdx group only, cardiomyocyte injury was increased markedly by acute elevations of mechanical stress induced by isoproterenol or brief aortic occlusion. Strikingly accelerated mortality and cardiac necrosis were also observed in the mdx group subjected to chronically increased cardiac mechanical stress via subtotal aortic constriction. Taken together, our results provide the first direct evidence that dystrophin serves to protect cardiomyocytes from mechanical stress and workload‐induced damage. Accordingly, reducing cardiac work in patients with dystrophin deficiency could be beneficial not only in treating established cardiomyopathy, but also in preventing the onset of cardiac disease.

p53 polymorphism in codon 72 and risk of human papillomavirus-induced cervical cancer: effect of inter-laboratory variation

An association between codon‐72 p53 polymorphism and risk of human papillomavirus (HPV)‐induced cervical cancer has been found recently, but it has been difficult to replicate. In this study, we assess the impact of inter‐laboratory variation in p53 genotyping on the validity of the proposed association. DNA specimens were randomly selected from 54 invasive, squamous cell carcinoma cases, 52 HPV‐negative, and 39 HPV‐positive controls from a previous case‐control study in Brazil. Codon‐72 polymorphism was blindly analyzed in three different laboratories. We calculated age‐ and race‐adjusted odds ratios (OR) and 95% confidence intervals (CI) using logistic regression for gauging the association between p53 polymorphism and cervical cancer risk. The proportions of the Arg/Arg, Arg/Pro, and Pro/Pro genotypes varied substantially among laboratories with Kappa coefficients in the 0.49–0.63 range. When disagreement between labs was allowed, the OR for the Arg/Arg genotype, compared to other forms, was as low as 1.5 (95% CI: 0.5–3.9). In contrast, the OR increased to 8.0 (95% CI: 2.3–28.5) after exclusion of discordant genotypes. Restricting the comparison to HPV‐positive controls increased the magnitude of the relation appreciably. After exclusion of all discordant diagnoses, the OR was 21.5 (95% CI: 3.4–137.8), whereas with disagreed genotypes the association was not significant (OR = 2.9, 95% CI: 0.7–11.9). Homozygous codon‐72 p53‐Arg apparently confers a higher susceptibility to HPV‐associated cervical tumorigenesis. However, exposure misclassification consequent to inter‐laboratory variation in protocols may affect the ability to detect the association. Int. J. Cancer 87:528–533, 2000.

Early venous thromboembolic event prophylaxis in traumatic brain injury with low-molecular-weight heparin: risks and benefits.

Traumatic brain injury (TBI) patients are known to be at high risk for venous thromboembolic events (VTEs). The Brain Trauma Foundation Guidelines (2007) state that low-molecular-weight heparin or unfractionated heparin should be used to prevent VTE complications, but suggest that there is an increased risk of expansion of intracranial hemorrhages (ICH) with VTE prophylaxis. In addition, it is unclear which treatment regimen (i.e., medication, dose, and timing) provides the best risk:benefit ratio in TBI patients. We reviewed all moderate-to-severe TBI patients admitted over a 5-year period to: (1) examine the occurrence of VTEs and their timing; (2) examine the symptomatic expansion of ICH while on VTE prophylaxis; and (3) compare the efficacy of two prophylactic agents: enoxaparin and dalteparin. Two-hundred eighty-seven patients were included. VTE prophylaxis was started 48-72 h post-trauma in all individuals who had no confounding coagulopathy, when two consecutive computed tomography (CT) scans revealed hemorrhage stability. VTEs occurred in 7.3% of treated patients, mostly within 2 weeks after trauma. Proximal VTEs occurred in 3.1% of treated patients. No significant difference in VTE rates was seen between enoxaparin (7.0%) and dalteparin (7.5%; p = 0.868). Moreover, the group treated with dalteparin was more severely injured (higher Injury Severity Score [p = 0.002]), had lower Glasgow Coma Scale (GCS) scores (p = 0.003), and had more inferior vena cava (IVC) filters placed (p = 0.007). The two groups did not show significant differences in the development of VTE when controlled for ISS and IVC filters (p = 0.819). Importantly, only one patient suffered a symptomatic expansion of ICH while on VTE prophylaxis, at 15 days post-trauma. These results suggest that current regimens of VTE prophylaxis used in our TBI population provide a relatively high level of protection against VTEs, and an extremely low risk of expanding ICH. They also suggest that there was no difference in VTE between dalteparin- and enoxaparin-treated patients.

Memory outcome after temporal lobe epilepsy surgery: corticoamygdalohippocampectomy versus selective amygdalohippocampectomy

OBJECT The aim of this study was to compare IQ and memory outcomes at the 1-year follow-up in patients with medically refractory mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis. All patients were treated using a corticoamygdalohippocampectomy (CAH) or a selective amygdalohippocampectomy (SelAH). METHODS The data of 256 patients who underwent surgery for MTLE were retrospectively evaluated. One hundred twenty-three patients underwent a CAH (63 [right side] and 60 [left side]), and 133 underwent an SelAH (61 [right side] and 72 [left side]). A comprehensive neuropsychological test battery was assessed before and 1 year after surgery, and the results were compared between the surgical procedures. Furthermore, seizure outcome was compared using the Engel classification scheme. RESULTS At 1-year follow-up, there was no statistically significant difference between the surgical approaches with respect to seizure outcome. Overall, IQ scores showed improvement, but verbal IQ decreased after left SelAH. Verbal memory impairment was seen after left-sided resections especially in cases of SelAH, and nonverbal memory decreased after right-sided resection, especially for CAH. Left-sided resections produced some improvement in nonverbal memory. Older age at surgery, longer duration of seizures, greater seizure frequency before surgery, and poor seizure control after surgery were associated with poorer memory. CONCLUSIONS Both CAH and SelAH can lead to several cognitive impairments depending on the side of the surgery. The authors suggest that the optimal type of surgical approach should be decided on a case-by-case basis.

Long-term functional benefits of selective dorsal rhizotomy for spastic cerebral palsy

OBJECT Large-scale natural history studies of gross motor development have shown that children with spastic cerebral palsy (CP) plateau during childhood and actually decline through adolescence. Selective dorsal rhizotomy (SDR) is a well-recognized treatment for spastic CP, but little is known about long-term outcomes of this treatment. The purpose of this study was to assess the durability of functional outcomes in a large number of patients through adolescence and into early adulthood using standardized assessment tools. METHODS The authors analyzed long-term follow-up data in children who had been evaluated by a multidisciplinary team preoperatively and at 1, 5, 10, and 15 years after SDR. These evaluations included quantitative, standardized assessments of lower-limb tone (Ashworth Scale), Gross Motor Function Measure (GMFM), and performance of activities of daily living (ADLs) by the Pediatric Evaluation of Disability Inventory in children who had been stratified by motor severity using the Gross Motor Function Classification System (GMFCS). In addition, group-based trajectory modeling (GBTM) was used to identify any heterogeneity of response to SDR among these treated children, and to find which pretreatment variables might be associated with this heterogeneity. Finally, a chart review of adjunct orthopedic procedures required by these children following SDR was performed. RESULTS Of 102 patients who underwent preoperative evaluations, 97, 62, 57, and 14 patients completed postoperative assessments at 1, 5, 10, and 15 years, respectively. After SDR, through adolescence and into early adulthood, statistically significant durable improvements in lower-limb muscle tone, gross motor function, and performance of ADLs were found. When stratified by the GMFCS, long-lasting improvements for GMFCS Groups I, II, and III were found. The GBTM revealed 4 groups of patients who responded differently to SDR. This group assignment was associated with distribution of spasticity (diplegia was associated with better outcomes than triplegia or quadriplegia) and degree of hip adductor spasticity (Ashworth score < 3 was associated with better outcomes than a score of 3), but not with age, sex, degree of ankle plantar flexion spasticity, or degree of hamstring spasticity. In a sample of 88 patients who had complete records of orthopedic procedures and botulinum toxin (Botox) injections, 52 (59.1%) underwent SDR alone, 11 (12.5%) received only Botox injections in addition to SDR, while 25 patients (28.4%) needed further lower-extremity orthopedic surgery after SDR. CONCLUSIONS In the majority of patients, the benefits of SDR are durable through adolescence and into early adulthood. These benefits include improved muscle tone, gross motor function, and performance of ADLs, as well as a decreased need for adjunct orthopedic procedures or Botox injections. The children most likely to display these long-term benefits are those in GMFCS Groups I, II, and III, with spastic diplegia, less hip adductor spasticity, and preoperative GMFM scores greater than 60.

Pediatric Low-Grade Ganglioglioma: Epidemiology, Treatments, and Outcome Analysis on 348 Children From the Surveillance, Epidemiology, and End Results Database

BACKGROUND Low-grade gangliogliomas/gangliocytomas (GGs) are rare tumors of the central nervous system that occur mostly in young people. Because of their rarity, large-scale, population-based studies focusing on epidemiology and outcomes are lacking. OBJECTIVE To use the Surveillance, Epidemiology, and End Results (SEER) data sets of the National Cancer Institute to study demographics, tumor location, initial treatment, and outcome data on low-grade GGs in children. METHODS SEER-STAT v8.1.2 identified all patients aged 0 to 19 years in the SEER data sets with low-grade GGs. Using the Kaplan-Meier method and Cox proportional hazard regression, we examined associations between these characteristics and survival. RESULTS There were 348 children with low-grade GGs diagnosed from 2004 to 2010, with a median follow-up of 37 months. Tumors were more prevalent in males (n = 208, 59.8%) than females (n = 140, 40.2%) (P < .001). Almost 63% occurred in children >10 years, whereas only 3.5% were found in those <1 year old. Approximately 50% were located in the temporal lobes, and only 3.7% and 3.5% were located in the brainstem and spinal cord, respectively. Surgery was performed on 91.6% of cases, with gross total resection achieved in 68.3%. Radiation was used in 3.2%. Young age (<1 year) and brainstem location were associated with worse overall survival. CONCLUSION This study shows that low-grade GGs occur in older children with a male preference. Gross total resection is achieved in the majority of cases, and radiation is rarely used. Although the majority of patients have an excellent prognosis, infants and patients with brainstem tumors have worse survival rates.

Development of a p53 responsive GFP reporter; identification of live cells with p53 activity.

p53 is among the most intensely studied human proteins because of its vital role as the prototype tumor suppressor. As a result, there are widespread applications for p53 functional analysis in biotechnology as it relates to cancer research. p53 is a potent sequence specific transcription factor, which induces the expression of a number of genes whose products mediate cell cycle arrest and apoptosis. Because the tumor suppressor activity of p53 is dependent on its transcription regulatory function, we have undertaken to develop a p53-responsive green fluorescent protein reporter strategy to enable the identification of live cells containing p53 transcriptional transactivation activity. We demonstrate within the use of GFP fluorescence to monitor both endogenous and plasmid derived p53 biochemical and biological activity. Identifying live cells with p53 activity through GFP fluorescence will have wide application for both in vitro and in vivo studies of the p53 tumor suppressor protein.

Short-term mortality following surgical procedures for the diagnosis of pediatric brain tumors: outcome analysis in 5533 children from SEER, 2004–2011

OBJECT Thirty-day mortality is increasingly a reference metric regarding surgical outcomes. Recent data estimate a 30-day mortality rate of 1.4-2.7% after craniotomy for tumors in children. No detailed analysis of short-term mortality following a diagnostic neurosurgical procedure (e.g., resection or tissue biopsy) for tumor in the US pediatric population has been conducted. METHODS The Surveillance, Epidemiology and End Results (SEER) data sets identified patients ≤ 21 years who underwent a diagnostic neurosurgical procedure for primary intracranial tumor from 2004 to 2011. One- and two-month mortality was estimated. Standard statistical methods estimated associations between independent variables and mortality. RESULTS A total of 5533 patients met criteria for inclusion. Death occurred within the calendar month of surgery in 64 patients (1.16%) and by the conclusion of the calendar month following surgery in 95 patients (1.72%). Within the first calendar month, patients < 1 year of age (n = 318) had a risk of death of 5.66%, while those from 1 to 21 years (n = 5215) had a risk of 0.88% (p < 0.0001). By the end of the calendar month following surgery, patients < 1 year (n = 318) had a risk of death of 7.23%, while those from 1 to 21 years (n = 5215) had a risk of 1.38% (p < 0.0001). Children < 1 year at diagnosis were more likely to harbor a high-grade lesion than older children (OR 1.9, 95% CI 1.5-2.4). CONCLUSIONS In the SEER data sets, the risk of death within 30 days of a diagnostic neurosurgical procedure for a primary pediatric brain tumor is between 1.16% and 1.72%, consistent with contemporary data from European populations. The risk of mortality in infants is considerably higher, between 5.66% and 7.23%, and they harbor more aggressive lesions.

Efficient and fast functional screening of microdystrophin constructs in vivo and in vitro for therapy of duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is an X-linked, lethal genetic disorder affecting the skeletal muscle compartment, and is caused by mutation(s) in the dystrophin gene. Gene delivery of microdystrophin constructs using adeno-associated virus (AAV) and antisense-mediated exon skipping restoring the genetic reading frame are two of the most promising therapeutic strategies for DMD. Both approaches use microdystrophin proteins either directly as a desired construct for gene delivery, using the capacity-limited AAV vectors, or as the therapeutic outcome of gene splicing. Although functionality of the resulting artificial dystrophin proteins can be predicted in silico, experimental evidence usually obtained in transgenic mice is required before human trials. However, the enormous number of potential constructs makes screening assays for dystrophin protein function in vitro and in vivo highly desirable. Here we present data showing that functionality of microdystrophins can be assessed using relatively simple and fast techniques.