NUDT5 promotes the growth,metastasis,and Warburg effect of IDH wild-type glioblastoma multiforme cells by upregulating TRIM47

Objective:To explore the regulatory mechanism of NUDT5 in glioblastoma multiforme(GBM).Methods:GEPIA database was used to predict the expressions of NUDT5 and tripartite motif family proteins 47(TRIM47)in GBM patients.RT-qPCR and Western blot analyses were performed to examine NUDT5 expression in GBM cells.LN-229 cell proliferation,migration as well as invasion were estimated by CCK-8,colony formation,wound healing,and Transwell assays following interference with NUDT5.ECAR assay,L-lactic acid kit,glucose detection kit,and ATP detection kit were applied for the detection of glycolysis-related indexes.Co-immunoprecipitation experiment was carried out to verify the relationship between NUDT5 and TRIM47.Results:GEPIA database showed that NUDT5 expression was significantly increased in GBM patients.Inhibiting the expression of NUDT5 in GBM cells significantly suppressed the viability,proliferation,invasion,migration,and glycolysis of GBM cells.Moreover,TRIM47 was highly expressed in GBM cells and interacted with NUDT5.Overexpression of TRIM47 partially reversed the inhibitory effect of NUDT5 downregulation on the proliferation,metastasis,and glycolysis of GBM cells.Conclusions:NUDT5 promotes the growth,metastasis,and Warburg effect of GBM cells by upregulating TRIM47.Both NUDT5 and TRIM47 can be used as targets for GMB treatment.

Glioblastoma multiforme:Diagnosis, treatment, and invasion

Glioblastoma multiforme(GBM) is an essentially incurable brain tumor, which has been explored for approximately a century. Nowadays, surgical resection, chemotherapy, and radiation therapy are still the standardized therapeutic options. However, due to the intrinsic invasion and metastasis features and the resistance to chemotherapy, the survival rate of glioblastoma patients remains unsatisfactory. To improve the current situation, much more research is needed to provide comprehensive knowledge of GBM. In this review, we summarize the latest updates on GBM treatment and invasion. Firstly, we review the traditional and emerging therapies that have been used for GBM treatment. Given the limited efficiency of these therapies, we further discuss the role of invasion in GBM recurrence and progression, and present current research progress on the mode and mechanisms of GBM invasion.

Nanosensitizers for sonodynamic therapy for glioblastoma multiforme: current progress and future perspectives

Glioblastoma multiforme(GBM) is the most common primary malignant brain tumor, and it is associated with poor prognosis. Its characteristics of being highly invasive and undergoing heterogeneous genetic mutation, as well as the presence of the blood–brain barrier(BBB), have reduced the efficacy of GBM treatment. The emergence of a novel therapeutic method, namely, sonodynamic therapy(SDT), provides a promising strategy for eradicating tumors via activated sonosensitizers coupled with low-intensity ultrasound. SDT can provide tumor killing effects for deep-seated tumors, such as brain tumors. However, conventional sonosensitizers cannot effectively reach the tumor region and kill additional tumor cells, especially brain tumor cells. Efforts should be made to develop a method to help therapeutic agents pass through the BBB and accumulate in brain tumors. With the development of novel multifunctional nanosensitizers and newly emerging combination strategies, the killing ability and selectivity of SDT have greatly improved and are accompanied with fewer side effects. In this review, we systematically summarize the findings of previous studies on SDT for GBM, with a focus on recent developments and promising directions for future research.

Neonatal erythema multiforme associated with a rotavirus infection:A case report

BACKGROUND Erythema multiforme(EM)is an extremely rare condition in neonates,and studies suggest its association with certain infections and neonatal vaccinations;however,few specific etiological agents have been identified.Rotavirus,a common pathogenic gastrointestinal virus in the neonatal period that is preventable via vaccination,has not been identified as a possible etiology.We report the case of a neonate who was referred for skin lesions presenting as EM,where a meticulous workup identified rotavirus as the sole causative agent.CASE SUMMARY A 14-day-old male infant was admitted to our hospital with a 1-day history of skin lesions.No medical history or medication intake was recorded.Except for the complaint of skin lesions,the caregivers denied any abnormal symptoms.Multiple tests,including routine laboratory evaluations,were performed to identify the cause of skin lesions.Serological tests for Immunoglobulin M for Toxoplasma,Rubella,Cytomegalovirus,Herpes Simplex Virus,and Epstein-Barr virus viral-capsid antigen were all negative.Multiple polymerase chain reaction(PCR)tests for respiratory viruses and bacterial pathogens were negative(including the severe acute respiratory syndrome coronavirus 2).Multiple PCR tests for gastrointestinal viruses and bacterial pathogens demonstrated evidence of rotavirus infection.No growth was reported in the blood and urine cultures.The patient received intravenous fluids for hydration;meanwhile,no other medications were prescribed.The lesions improved rapidly without specific treatment,and full recovery was achieved within a week.CONCLUSION The possibility of rotavirus,a major cause of pediatric gastrointestinal infections,being a trigger for neonatal EM should be considered.

Exploring Chemovar-Specific Cannabis Extracts Quantification and Evaluation of Cytotoxic Compounds for Targeting Glioblastoma Multiforme

Glioblastoma Multiforme (GBM) represents one of the most aggressive and metastatic brain tumors, with a dismal success rate of less than three percent after five years, particularly in tumors with active immune checkpoints. This necessitates the development of targeted endogenous agents for precise GBM treatment. Previous experiments utilizing Chemovar Specific Cannabis Extractions (CSCEs), fractionated with polar solvents and quantified using Liquid and Gas Column Chromatography combined with Mass Spectrometry (LC/GCMS), have shown reduced viability and motility in human GBM cell lines. However, the complexity of the botanical substance has hindered the personalization of standard cannabis medicines for GBM due to unknown synergistic effects of multiple compounds. To address this limitation, our study focuses on exposing AM251 cells to chemovar fractions extracted using a non-polar solvent, thereby isolating a broader spectrum of constituents. By employing LC/GCMS in conjunction with Nuclear Magnetic Resonance (NMR), we have identified and quantified nine* compounds present in the non-polar CSCE that exhibit significant efficacy (0.1 μM) in inducing cytotoxicity* in GBM tumor cells. Conversely, the polar fraction in our experiment did not demonstrate efficacy against UM251 cells. The quantification of individual compounds within a cannabis extraction that selectively induces cell death in brain tumors holds promise for guiding future research and facilitating the development of a standardized CSCE for GBM therapy.

Subcurative radiation significantly increases cell proliferation, invasion, and migration of primary glioblastoma multiforme in vivo

Tumor cell proliferation, infiltration, migration, and neovascularization are known causes of treatment resistance in glioblastoma multiforme(GBM). The purpose of this study was to determine the effect of radiation on the growth characteristics of primary human GBM developed in a nude rat. Primary GBM cells grown from explanted GBM tissues were implanted orthotopically in nude rats. Tumor growth was confirmed by magnetic resonance imaging on day 77(baseline) after implantation. The rats underwent irradiation to a dose of 50 Gy delivered subcuratively on day 84 postimplantation(n = 8), or underwent no radiation(n = 8). Brain tissues were obtained on day 112(nonirradiated) or day 133(irradiated). Immunohistochemistry was performed to determine tumor cell proliferation(Ki-67) and to assess the expression of infiltration marker(matrix metalloproteinase-2, MMP-2) and cell migration marker(CD44). Tumor neovascularization was assessed by microvessel density using von-Willebrand factor(vWF) staining. Magnetic resonance imaging showed well-developed, infiltrative tumors in 11 weeks postimplantation. The proportion of Ki-67-positive cells in tumors undergoing radiation was(71 ± 15)% compared with(25 ± 12)% in the nonirradiated group(P = 0.02). The number of MMP-2-positive areas and proportion of CD44-positive cells were also high in tumors receiving radiation, indicating great invasion and infiltration. Microvessel density analysis did not show a significant difference between nonirradiated and irradiated tumors. Taken together, we found that subcurative radiation significantly increased proliferation, invasion, and migration of primary GBM. Our study provides insights into possible mechanisms of treatment resistance following radiation therapy for GBM.

A Phase II Study of Antineoplastons A10 and AS2-1 in Adult Patients with Recurrent Glioblastoma Multiforme: Final Report (Protocol BT-21)

Treatment of recurrent glioblastoma multiforme (RGBM) creates one of the most difficult challenges to neuro-oncology. The purpose of this study is to evaluate the outcome of adults with high-grade glioma with special attention to RGBM patients treated with Antineoplastons (ANP) A10 and AS2-1 injections. The study was conducted according to Protocol BT-21, which accrued patients who failed standard radiation therapy (RT) and chemotherapy. There were 40 candidates registered in the study. Among the intent-to-treat (ITT) population, there were 30 cases of RGBM that progressed during and after prior treatment, 4 patients with anaplastic astrocytoma (AA), 1 with anaplastic mixed glioma (AMG), and 5 with persistent GBM. The aim of this paper is to evaluate the responses, survival and toxicity of all 40 patients, the efficacy in 30 patients with RGBM, and in 24 patients with RGBM who received at least 28 days of ANP (ERGBM). All RGBM patients were treated before with RT and chemotherapy, except one patient who only had surgery (patient refused radiation). In this group, 63% had one recurrence, 30% had two recurrences, and 7% had three recurrences. The median duration of ANP and ITT was 12 weeks and the median dosage of ANP A10 was 6.52 g/kg/d and ANP AS2-1 was 0.23 g/kg/d. Responses were assessed by gadolinium-enhanced magnetic resonance imaging (MRI) repeated every eight weeks. In the ITT population, objective responses (ORs) were determined in 10% of cases (complete response—CR, and partial response—PR in 5% each). Progression-free survival (PFS) in ITT at six months was 17.5%. Overall survival (OS) was 28.3% at one year, 2.6% at two years, five and ten years. In the RGBM population, objective responses (ORs) were determined in 13.3% of cases (CR and PR in 6.7% each). PFS in RGBM at six months was 16.7%. OS was 34.7% at one year, 3.47% at two years, five?and ten years. In the ERGBM population, ORs were determined in 16.7% of cases (CR and PR in?8.3% each). PFS in ERGBM at six months was 20.8%, OS was 39.3% at one year, 4.4% at two years, five and ten years. The treatment was well-tolerated with reversible Grades 3 and 4 toxicity in 17.5% of patients (7 patients who experienced multiple toxicities) and no chronic toxicity. In conclusion, the study reached efficacy endpoint. ANP is well-tolerated and compares favorably to the current treatment for RGBM.

Gliosarcoma:A rare variant of glioblastoma multiforme in paediatric patient:Case report and review of literature

Gliosarcoma is rare central nervous system tumour and a variant of glioblastoma multiforme with bimorphic histological pattern of glial and sarcomatous differentiation. It occurs in elderly between 5^(th) and 6^(th) decades of life and extremely rare in children. It is highly aggressive tumour and managed like glioblastoma multiforme. A 12-year-old female child presented with complaints of headache and vomiting from 15d and blurring of vision from 3d. Magnetic resonance imaging of brain shows heterogeneous mass in right parieto-occipital cortex. A right parieto-occipito-temporal craniotomy with complete excision of mass revealed a primary glioblastoma on histopathological investigation. Treatment consists of maximum surgical excision followed by adjuvant radiotherapy. The etiopathogenesis, treatment modalities and prognosis is discussed. The available literature is also reviewed.

Immunophenotypic signature of primary glioblastoma multiforme: A case of extended progression free survival

Glioblastoma-multiforme(GBM), the most aggressive glial tumor, has a worldwide age-adjusted incidence ranging from 0.59-3.69/100000 persons. Despite current multimodal-treatment approach, median-survival time and progression-free survival(PFS) remains short. Glioblastomas display a variety of molecular alterations, which necessitates determining which of these have a prognostic significance. This is a case of a 45-yearold patient who presented with progressive slurring of speech and features of raised intracranial pressure. Computed tomography(CT) scan revealed a large heterogeneously enhancing lesion in the left front-temporalperisylvian region with solid, cystic areas, suggestive of malignant glioma. Partial tumor-excision was followed by concurrent chemo-radiotherapy. Histopathologically, the tumor was astrocytoma grade-IV. Patient had an extended PFS of 12 mo, with an overall survival of 26 mo. Primary-GBM was confirmed using molecular markers and the immunophenotypic signature was defined by evaluating systemic expression of human telomerase reverse transcriptase, interleukin-6, neutrophil-lymphocyte ratio, tissue inhibitor of metalloproteinases-1, human chitinase-3-like-protein-1(YKL-40) and high mobility group-A1. Current findings suggest that this signature can identify worst outcomes, independent of clinical criteria.

Hypertensive-Nimodipine Therapy for Middle Cerebral Artery Vasospasm after Resection of Glioblastoma Multiforme: A Case Report and Literature Review

Delayed cerebral ischemia (DCI) due to post-brain tumor resection vasospasm is an often unrecognized yet debilitating complication. We present a patient with DCI after the resection of glioblastoma multiforme (GBM). To our knowledge, this is the first report on DCI after GBM resection. A 52-year-old female patient with headache for one month underwent subtotal resection of a left temporal GBM encasing the proximal middle cerebral artery (MCA). She was well during the immediate postoperative period but developed right upper limb dense monoparesis on postoperative day four with computed tomographic angiography confirming left MCA vasospasm. Symptoms were significantly alleviated with weeklong hypertensive therapy and nimodipine administration;however they recurred soon after cessation of treatment. A high index of clinical suspicion is needed for the diagnosis of post-tumor resection DCI. Any new postoperative neurological deficit that cannot be explained by hemorrhage, seizures or infection should be expeditiously investigated by angiography or transcranial Doppler sonography. Prompt initiation of hypertensive and nimodipine therapy can possibly reverse neurological deficit. Treatment should be guided by Doppler, angiographic or perfusion imaging studies and not by clinical improvement alone.

Preliminary Findings on the Use of Targeted Therapy with Pazopanib and Other Agents in Combination with Sodium Phenylbutyrate in the Treatment of Glioblastoma Multiforme

The most common and aggressive type of brain tumor is glioblastoma multiforme (GBM). The prognosis for GBM remains poor with a five-year survival rate between 1% and 2%. The prospects for patients with recurrent GBM (RGBM) are much worse, with the majority dying within 6 months. This publication provides a brief description of the treatment of 11 GBM patients treated with sodium phenylbutyrate (PB) in combination with pazopanib, m-TOR inhibitors, and other agents. The treatment was associated with tolerable side effects and resulted in objective responses in 54.5% of cases (complete response 18.2%, partial response 36.3%) and 27.3% cases of stable disease. The preferable treatment regimen consisted of PB, pazopanib, dasatinib, everolimus, and bevacizumab (BVZ). For various reasons not all patients were compliant with the treatment regimen. In patients who strictly complied with the treatment plan, all responded as CR or PR. Based on preliminary findings, the authors propose further phase I/II clinical trials with PB in combination with pazopanib, dasatinib, everolimus, and BVZ in patients with RGBM who failed standard surgery, radiation therapy and chemotherapy. With proper dose reductions, the treatment appears to be well-tolerated. Molecular profiling of patient subgroups with favorable genomic signatures may help to select patients for future studies.

Recurrent Glioblastoma Multiforme—A Strategy for Long-Term Survival

Recurrent GBM (RGBM) has a highly unfavorable prognosis with majority of patients dying within 6 months and no standard treatments available. Antineoplaston (ANP) A10 and AS2-1 injections underwent Phase II trials in RGBM patients, which reported a long-term overall survival (OS) in a small percentage of patients. The additional Phase II studies BT-07, and BT-21 with ANP in GBM also revealed cases of a long-term OS. ANP shares active ingredients with metabolites of sodium phenylbutyrate (PB), which was used in private practice setting in combination of targeted and chemotherapeutic agents for the treatment of RGBM. The treatment contributed to cases of rapid complete response (CR) and significant OS. This paper provides case studies of three patients treated with ANP under Phase II protocols and two patients treated with PB in combination with targeted therapy, who obtained CR and long-term OS. Based on these studies and basic research on the effects of ANP and PB on the genome of GBM and review of results of preclinical and clinical research on targeted agents, the authors suggest a new strategy for successful treatment of RGBM. They propose Phase I/II clinical trials with ANP and PB in combination with targeted agents, bevacizumab (BVZ), pazopanib, dasatinib and everolimus in patients with RGBM after failure of standard surgery, radiation therapy (RT) and chemotherapy including temozolomide (TMZ) to be conducted to evaluate survival, response and toxicity in these patients.

Prognostic significance of annexin VII expression in glioblastomas multiforme in humans

OBJECT:Glioblastoma multiforme(GBM)is the most common and lethal primary brain tumor in adults.It isnearly uniformly fatal,with a median survival time of approximately l year,despite modem treatment modalities.Nevertheless,a range of survival times exists around this median.Efforts to understand why some patients livelonger or shorter than the average may provide insight into the biology of these neoplasms.The annexin VII(ANX7)gene is located on the human chromosome 10q21,a site long hypothesized to harbor tumor

Exploiting the inherent invasive property to treat glioblastoma multiforme

Glioblastoma multiforme(GBM)is the most malignant brain tumor with high infiltration.The routine surgical resection followed by radiation and chemotherapy only provides patients with a survival period ranging 12–15months.Here,I propose that the high invasiveness property of the GBM cells be exploited to treat this deadly disease.That is,instead of inhibiting the dissemination of GBM cells,we should take advantage of the high mobility of the disseminated GBM cells and directionally induce these cells to return to the center of surgical resection cavity of the primary neoplasm and subsequently kill them.This idea may provide a new promise to defeat this deadly disease.

Molecular pathogenesis of glioblastoma multiforme: Nuances, obstacles, and implications for treatment

Glioblastoma multiforme(GBM), the literal apogee on the hierarchy of malignant brain tumors, remains one of the greatest therapeutic challenges in oncology andmedicine. Historically this may be contextualized in the fact that the medical and scientific communities have had a very elementary understanding of its intricate and complex pathophysiology. The last 10-15 years have yielded a number of studies that have elucidated much of the molecular and genetic complexities of GBM that underlie its pathogenesis. Excitingly, some of these discovered genetic mutations and molecular profiles in GBM have demonstrated value in prognostication and utility in predicting response to treatment. Despite this, however, treatment options for patients have remained somewhat limited. These treatment options are expected to expand with the availability of new data and with the transition of novel treatment modalities from animal to human studies. This paper will have a threefold objective: provide an overview of the traditional paradigm in understanding and treating GBM, describe recent discoveries in the molecular pathogenesis of GBM against this historical backdrop, and acquaint the reader with new treatment modalities that hold significant therapeutic potential for patients.

Glioblastoma multiforme with metastasis to lung,bone,and chest wall:a case report

Glioblastoma multiforme(GBM)is a common brain tumor that rarely metastasizes extra-cranially.We present the case of a 40-year-old male with left temporal GBM who underwent craniotomy followed by radiotherapy and chemotherapy.Postoperative MRI scans at different time intervals demonstrated a good response.Eleven months after the initial diagnosis,there were no clinical or radiological signs suggesting recurrence.However,the tumor showed metastasis simultaneously to the chest wall,lungs,and bone,despite 2 cycles of chemotherapy.The patient developed paraplegia 14 months after the initial diagnosis and died due to systemic failure 19 months after diagnosis.Extracranial metastasis of GBM is extremely rare.We present the unusual case of a patient with GBM who showed simultaneous metastasis to the lungs,bone,and chest wall.The prognosis of patients with extracranial metastasis of glioblastomas is very poor,regardless of chemoradiotherapy.Newer approaches,such as immunotherapy and anti-angiogenic therapy,need to be further studied.

A short perspective on gene therapy:Clinical experience on gene therapy of gliomablastoma multiforme

More than two decades have passed since the first gene therapy clinical trial was conducted.During this time,we have gained much knowledge regarding gene therapy in general,but also learned to understand the fear that persists in society.We have experienced drawbacks and successes.More than 1700 clinical trials have been conducted where gene therapy is used as a means for therapy.In the very first trial,patients with advanced melanoma were treated with tumor infiltrating lymphocytes genetically modified ex-vivo to express tumor necrosis factor.Around the same time the first gene therapy trial was conducted,the ethical aspects of performing gene therapy on humans was intensively discussed.What are the risks involved with gene therapy?Can we control the technology?What is ethically acceptable and what are the indications gene therapy can be used for?Initially,gene therapy was thought to be implemented mainly for the treatment of monogenetic diseases,such as adenosine deaminase deficiency.However,other therapeutic areas have become of interest and currently cancer is the most studied therapeutic area for gene therapy based medicines.In this review I will be giving a short introduction into gene therapy and will direct the discussion to where we should go from here.Furthermore,I will focus on the use of the Herpes simplex virus-thymidine kinase for gene therapy of malignant gliomas and highlight the efficacy of gene therapy for the treatment of malignant gliomas,but other strategies will also be mentioned.

Visual Allesthesia in a Patient with Glioblastoma Multiforme

Purpose: To report a rare case of visual allesthesia in a patient with glioblastoma multiforme. Material - Methods : A 46 – year old male presented in emergency ophthalmologic department complaining for difficulties in performing tasks related to color discrimination in his occupation (PC technician). The patient underwent a thorough ophthalmological examination and then he was referred to the neurological department for further evaluation. Results: The patient presented an atypical pattern of color perception disturbance. His best corrected visual acuity decreased progressively during hospitalization. He also experienced visual allesthesia paroxysmally (illusory left homonymous transpositions of subjects viewed in the right homonymous visual field). The visual field evaluation revealed homonymous left hemianopsia. Magnetic resonance imaging revealed glioblastoma multiforme confirmed by biopsy. Conclusions: A thorough ophthalmological and neuro-imaging control is suggested in patients with sudden color perception disturbance. Patients with temporal or occipital cortex damage may experience visual allesthesia.

Protracted Adjuvant Temozolomide in Glioblastoma Multiforme

Purpose: Radiotherapy with concurrent temozolomide (TMZ), followed by 6 cycles of adjuvant TMZ, is the standard of care for newly diagnosed Glioblastoma Mulltiforme (GBM). However tumor progression is the role with median survival of almost 14 months. With lack of effective second line chemotherapy, many physicians and some guidelines advocate prolonged use of adjuvant TMZ more than 6 months. We conduct this study to test the efficacy of protracted adjuvant conventional dose TMZ over the standard 6 doses of adjuvant TMZ. Material and Methods: This phase II trial enrolled patients newly diagnosed as GBM, older than age 18 years, with a Karnofsky performance score (KPS) of ≥60, Neurological Performance Scale (NPS) of ≤3. Patients were randomly assigned to the standard concurrent chemoradiotherapy (CCRT) followed by 6 cycles of adjuvant TMZ or the same treatment with more than 6 cycles of adjuvant chemotherapy extended as long as the patient in good performance, with no unacceptable toxicity, no signs of disease progression. The primary end point was OS. Results: A total of 59 patients were recruited in the study and were randomized in two arms. 29 patients joined arm 1 aiming at receiving CCRT followed by adjuvant 6 cycles TMZ (6 cycles arm) and 30 joined arm 2 aiming at receiving the same treatment with more than 6 cycles of TMZ (>6 cycles). 16 patients managed to complete the adjuvant 6 cycles in arm 1. 19 patients in arm 2, completed the 6 cycles with additive more doses with a median of 11 cycles (range: 8 - 23 cycles). Median PFS was 12.1 months for (6 cycles) arm, and 18.8 months for (>6 cycles) arm, HR 0.88 (95% CI: 1.185 - 4.901) (P 0.015);the overall survival for (6 cycles) arm was 18.1 months, versus 24.1 months, HR 0.70 (95% CI: 1.007 - 4.037) (P 0.048). No significant added toxicity was notice and the 4 weekly TMZ was well tolerated. Conclusion: This study concluded that protracted adjuvant TMZ after concurrent chemoradiotherapy could be a feasible strategy for GBM. This strategy warrants a large phase III randomized trial.

Consideration of transmembrane water exchange in pharmacokinetic model significantly improves the accuracy of DCE-MRI in estimating cellular density:A pilot study in glioblastoma multiforme

Transmembrane water exchange(TWE)including transcytolemmal water exchange and transvascular water exchange is involved in many in vivo measurements and makes different contributions to the measuring results.In this study,we focus on the potential influence of TWE on the cell density parameter,intracellular water mole fraction pi,derived by dynamic contrast enhanced-magnetic resonance imaging(DCE-MRI)which has been reported as a technique to characterize perfusion and vascularization of tissues,but its accuracy in measuring cell density(or interstitial space)has been questioned.Sixteen patients with glioblastoma multiforme(GBM)were enrolled since GBM shows strong intratumor heterogeneity in both cell density and TWE.All the subjects were collected with DCE-MRI and apparent diffusion coefficient(ADC)map.The latter was considered as a valid surrogate of cell density.Extended Tofts(eTofts)model considering TWE as infinitely large variables and shutter-speed model(SSM)considering TWE as finite ones were used to fit DCE-MRI data.Monte Carlo(MC)and finite difference(FD)methods were used to simulate the influence of TWE on DCE-MRI-derived pi and ADC,respectively.The eTofts model shows a significant overestimation of pi in comparison with SSM in GBM(P<0.001),which is in accordance with MC simulations,and this overestimation shows dependence on the intra-to-extracellular water exchange rate constant(kio).Significant negative correlations between ADC and SSM-derived pi were found in both voxel-wise analyses(t-test P<0.001,average r=-0.74)and inter-subject comparisons(r=-0.63,P=0.009).But no consistent voxel-wise correlations(P>0.05)and a weaker inter-subject negative correlation(r=-0.56,P=0.02)were found between ADC and eTofts-derived pi.Further experimental and FD results revealed that kio made a limited contribution to ADC values in the physiological kio range in GBM,supporting ADC as a valid biomarker of cell density.These results suggest that the DCE-MRI pharmacokinetic shutter-speed model could significantly improve its accuracy in cell density estimation because of the considering transmembrane water exchange.