Evolving evidence implicates cytomegalovirus as a promoter of malignant glioma pathogenesis

A novel deep learning model for glioma epilepsy associated with the identification of human cytomegalovirus infection injuries based on head MR

Purpose

In this study, a deep learning model was established based on head MRI to predict a crucial evaluation parameter in the assessment of injuries resulting from human cytomegalovirus infection: the occurrence of glioma-related epilepsy. The relationship between glioma and epilepsy was investigated, which serves as a significant indicator of labor force impairment.

Methods

This study enrolled 142 glioma patients, including 127 from Shengjing Hospital of China Medical University, and 15 from the Second Affiliated Hospital of Dalian Medical University. T1 and T2 sequence images of patients' head MRIs were utilized to predict the occurrence of glioma-associated epilepsy. To validate the model's performance, the results of machine learning and deep learning models were compared. The machine learning model employed manually annotated texture features from tumor regions for modeling. On the other hand, the deep learning model utilized fused data consisting of tumor-containing T1 and T2 sequence images for modeling.

Results

The neural network based on MobileNet_v3 performed the best, achieving an accuracy of 86.96% on the validation set and 75.89% on the test set. The performance of this neural network model significantly surpassed all the machine learning models, both on the validation and test sets.

Conclusion

In this study, we have developed a neural network utilizing head MRI, which can predict the likelihood of glioma-associated epilepsy in untreated glioma patients based on T1 and T2 sequence images. This advancement provides forensic support for the assessment of injuries related to human cytomegalovirus infection.

The Basis and Advances in Clinical Application of Cytomegalovirus-Specific Cytotoxic T Cell Immunotherapy for Glioblastoma Multiforme

A high percentage of malignant gliomas are infected by human cytomegalovirus (HCMV), and the endogenous expression of HCMV genes and their products are found in these tumors. HCMV antigen expression and its implications in gliomagenesis have emerged as a promising target for adoptive cellular immunotherapy (ACT) strategies in glioblastoma multiforme (GB) patients. Since antigen-specific T cells in the tumor microenvironments lack efficient anti-tumor immune response due to the immunosuppressive nature of glioblastoma, CMV-specific ACT relies on in vitro expansion of CMV-specific CD8⁺ T cells employing immunodominant HCMV antigens. Given the fact that several hurdles remain to be conquered, recent clinical trials have outlined the feasibility of CMV-specific ACT prior to tumor recurrence with minimal adverse effects and a substantial improvement in median overall survival and progression-free survival. This review discusses the role of HCMV in gliomagenesis, disease prognosis, and recent breakthroughs in harnessing HCMV-induced immunogenicity in the GB tumor microenvironment to develop effective CMV-specific ACT.

Mechanisms of Survival of Cytomegalovirus-Infected Tumor Cells

Human cytomegalovirus (HCMV) DNA and proteins are often detected in malignant tumors, warranting studies of the role that HCMV plays in carcinogenesis and tumor progression. HCMV proteins were shown to regulate the key processes involved in tumorigenesis. While HCMV as an oncogenic factor just came into focus, its ability to promote tumor progression is generally recognized. The review discusses the viral factors and cell molecular pathways that affect the resistance of cancer cells to therapy. CMV inhibits apoptosis of tumor cells, that not only promotes tumor progression, but also reduces the sensitivity of cells to antitumor therapy. Autophagy was found to facilitate either cell survival or cell death in different tumor cells. In leukemia cells, HCMV induces a "protective" autophagy that suppresses apoptosis. Viral factors that mediate drug resistance and their interactions with key cell death pathways are necessary to further investigate in order to develop agents that can restore the tumor sensitivity to anticancer drugs.

Cytomegalovirus DNA in non-glioblastoma multiforme brain tumors of infants

PURPOSE

CMV antigens have been detected in some brain tumors specially glioblastoma multiforme (GBM). As brain tumors in the first years of life are among the most aggressive neoplasms with poor prognosis, novel therapeutic options like targeted therapy against virus antigens are demanded. Infantile central nervous system tumors, other than GBM, have not been so far studied for CMV. To our best knowledge, this is the first study in which the presence of CMV-DNA, as a potential viral target for therapy, in non-GBM infantile brain tumors has been investigated.

METHODS

The paraffin blocks of non-GBM brain neoplasms of 36 infants (age < 24 months) who were operated on between 2006 and 2016 were examined for CMV-DNA, using real-time polymerase chain reaction (PCR). Paraffin blocks of CMV infected lung tissue were used as positive control. Extraction and amplification of β2 microglobulin gene from each tumor tissue were carried as positive internal control. We also assayed 25 paraffin blocks of meningomyelocele for CMV DNA as negative tissue controls.

RESULTS

Histopathological diagnoses consisted of 13 glial/neuroglial tumors (36.1%), 8 ependymomas (22.2%), 7 medulloblastomas (19.4%), 3 choroid plexus tumors (8.3%), 2 atypical teratoid rhabdoid tumors (5.6%), 2 embryonal CNS tumors (5.6%), and 1 germ cell tumor (2.8%). We could not detect CMV DNA in all samples examined.

CONCLUSION

Although CMV may be associated with GBM, no role could be proposed for this virus in development of non-GBM infantile brain tumors. Further investigations on larger series of brain tumors should be conducted to confirm or rule out our conclusion.

Immunotherapies for pediatric cancer: current landscape and future perspectives

The advent of immunotherapy has revolutionized how we manage and treat cancer. While the majority of immunotherapy-related studies performed to date have focused on adult malignancies, a handful of these therapies have also recently found success within the pediatric space. In this review, we examine the immunotherapeutic agents that have achieved the approval of the US Food and Drug Administration for treating childhood cancers, highlighting their development, mechanisms of action, and the lessons learned from the seminal clinical trials that ultimately led to their approval. We also shine a spotlight on several emerging immunotherapeutic modalities that we believe are poised to have a positive impact on the treatment of pediatric malignancies in the near future.

Accelerated cancer aggressiveness by viral oncomodulation: New targets and newer natural treatments for cancer control and treatment

An infectious etiology for a number of cancers has been entertained for over 100 years and modern studies have confirmed that a number of viruses are linked to cancer induction. While a large number of viruses have been demonstrated in a number of types of cancers, most such findings have been dismissed in the past as opportunistic infections, especially with persistent viruses with high rates of infectivity of the world’s populations. More recent studies have clearly shown that while not definitely causing these cancers, these viruses appear capable of affecting the biology of these tumors in such a way as to make them more aggressive and more resistant to conventional treatments. The term oncomodulatory viruses has been used to describe this phenomenon. A number of recent studies have shown a growing number of ways these oncomodulatory viruses can alter the pathology of these tumors by affecting cell-signaling, cell metabolism, apoptosis mechanisms, cell-cell communication, inflammation, antitumor immunity suppression, and angiogenesis. We are also learning that much of the behavior of tumors depends on cancer stem cells and stromal cells within the tumor microenvironment, which participate in extensive, dynamic crosstalk known to affect tumor behavior. Cancer stem cells have been found to be particularly susceptible to infection by human cytomegalovirus. In a number of studies, it has been shown that while only a select number of cells are actually infected with the virus, numerous viral proteins are released into cancer and stromal cells in the microenvironment and these viral proteins are known to affect tumor behavior and aggressiveness.

Is the presence of HCMV components in CNS tumors a glioma-specific phenomenon?

Background

Human cytomegalovirus (HCMV) has been associated with malignant gliomas. The purpose of the present study was to investigate the presence of HCMV in common non-glial tumors of the central nervous system (CNS) and to determine whether it is a glioma-specific phenomenon.

Methods

Using HCMV-specific immunohistochemical staining, HCMV proteins IE1–72 and pp65 were examined in 65 meningiomas (benign, atypical and malignant), 45 pituitary adenomas, 20 cavernous hemangiomas, and 30 metastatic carcinomas specimens. HCMV DNA was also measured in these tumor tissues and the peripheral blood from patients using nested PCR.

Results

In meningioma, IE1–72 was detected in 3.1% (2/65) and pp65 was detected in 4.6% (3/65), whereas no IE1–72 and pp65 were detected in atypical and malignant meningioma. A low level of IE1–72 immunoreactivity 6.7% (2/30) was detected in metastatic carcinoma; pp65 was not detected. No HCMV components were detected in pituitary adenoma and cavernous hemangioma. The results of immunohistochemical staining were confirmed by HCMV-specific PCR. HCMV DNA was not detected in the peripheral blood of the non-glial CNS tumors patients.

Conclusions

Our results demonstrate that the presence of HCMV components is not an entirely glioma-specific phenomenon, and that HCMV is present in a low percentage in some non-glioma CNS tumors. Comparing HCMV-positive non-glial CNS tumors with HCMV-positive gliomas may cast light on the mechanism and role of HCMV in CNS tumors.

Electronic supplementary material

The online version of this article (10.1186/s12985-019-1198-5) contains supplementary material, which is available to authorized users.

Host Genetics of Cytomegalovirus Pathogenesis

Human cytomegalovirus (HCMV) is a ubiquitous herpes virus (human herpes virus 5) with the highest morbidity and mortality rates compared to other herpes viruses. Risk groups include very young, elderly, transplant recipient, and immunocompromised individuals. HCMV may cause retinitis, encephalitis, hepatitis, esophagitis, colitis, pneumonia, neonatal infection sequelae, inflammatory, and age-related diseases. With an arsenal of genes in its large genome dedicated to host immune evasion, HCMV can block intrinsic cellular defenses and interfere with cellular immune responses. HCMV also encodes chemokines, chemokine receptors, and cytokines. Therefore, genes involved in human viral defense mechanisms and those encoding proteins targeted by the CMV proteins are candidates for host control of CMV infection and reactivation. Although still few in number, host genetic studies are producing valuable insights into biological processes involved in HCMV pathogenesis and HCMV-related diseases. For example, genetic variants in the immunoglobulin GM light chain can influence the antibody responsiveness to CMV glycoprotein B and modify risk of HCMV-related diseases. Moreover, CMV infection following organ transplantation has been associated with variants in genes encoding toll-like receptors (TLRs), programmed death-1 (PD-1), and interleukin-12p40 (IL-12B). A KIR haplotype (2DS4+) is proposed to be protective for CMV activation among hematopoietic stem cell transplant patients. Polymorphisms in the interferon lambda 3/4 (IFNL3/4) region are shown to influence susceptibility to CMV replication among solid organ transplant patients. Interestingly, the IFNL3/4 region is also associated with AIDS-related CMV retinitis susceptibility in HIV-infected patients. Likewise, interleukin-10 receptor 1 (IL-10R1) variants are shown to influence CMV retinitis development in patients with AIDS. Results from genome-wide association studies suggest a possible role for microtubule network and retinol metabolism in anti-CMV antibody response. Nevertheless, further genetic epidemiological studies with large cohorts, functional studies on the numerous HCMV genes, and immune response to chronic and latent states of infection that contribute to HCMV persistence are clearly necessary to elucidate the genetic mechanisms of CMV infection, reactivation, and pathogenesis.

The Inhibition of miR-144-3p on Cell Proliferation and Metastasis by Targeting TOP2A in HCMV-Positive Glioblastoma Cells

Glioblastoma (GBM), the most common type of primary tumor in the central nervous system, is a very aggressive brain tumor with poor prognosis and a high recurrence rate. Increasing evidence suggests that human cytomegalovirus (HCMV) infection is related to GBM and leads to GBM cell growth and metastasis. MicroRNAs are important regulators in the growth and metastasis of glioblastoma. This study aimed to demonstrate the role of miR-144-3p in HCMV-positive glioblastoma. We found that, after HCMV infection, the expression of miR-144-3p decreased, whereas the expression of TOP2A increased. Bioinformatics analyses indicated that miR-144-3p directly targets the TOP2A 3'-UTR (Untranslated Region). We discovered that the overexpression of miR-144-3p downregulated the overexpression of TOP2A and inhibited the proliferation, clone formation, and invasion of HCMV-positive glioma in vitro. Taken together, these results show that miR-144-3p inhibited growth and promoted apoptosis in glioma cells by targeting TOP2A.

TLR3 regulates PD-L1 expression in human cytomegalovirus infected glioblastoma

Glioblastoma, the most common primary brain tumor of adults, is characterized by poor survival rates. Programmed death ligand 1 (PD-L1, CD274) has been implicated in the immune escape of glioblastoma. The presence of human cytomegalovirus (HCMV) in glioblastoma multiforme (GBM) has sparked considerable interest and controversy. The exposure of toll-like receptor 3 (TLR3) to pathogens induces an antiviral state in cells or in animals. In the current study, the expression of PD-L1 and TLR3 in HCMV-infected glioma specimens was observed to be higher compared to the control. We therefore investigated if PD-L1 expression in glioblastoma is mediated by TLR3 triggering in HCMV infected glioblastoma. TLR3 siRNA transfections were utilized to identify the induction of PD-L1 via TLR3 triggering in HCMV infected cell lines. Also, IL-8 and TGF-β were detected by ELISA for the antitumor role of TLR3. Thus, we propose a novel immune treatment using a combination of PD-L1 blockade with TLR3 triggering against HCMV infected glioblastoma.

Impact of Human Cytomegalovirus Infection and its Immune Response on Survival of Patients with Ovarian Cancer

Human cytomegalovirus (HCMV) has been detected in various types of tumors. We studied the prevalence of HCMV in ovarian cancer and its relation to clinical outcome. Paraffin-embedded tissues obtained prospectively from 45 patients with ovarian cancer and 30 patients with benign ovarian cystadenoma were analyzed for expression of HCMV immediate-early protein (IE) and HCMV tegument protein (pp65) by immunohistochemistry. Plasma was analyzed for HCMV serology. HCMV-IgG levels were higher in patients with ovarian cancer or benign cystadenoma than in age-matched controls (P = .002, P < .0001, respectively). HCMV IgM was detected in 12% of ovarian cancer patients and 3% of patients with benign tumors but was absent in controls. In patients with ovarian cancer, higher IgG levels were associated with better outcomes (P = .04). Extensive HCMV-IE protein expression was detected in 75% of ovarian cancers and 26% of benign tumors; pp65 was detected in 67% of ovarian cancers and 14% of benign tumors. A higher grade of HCMV infection was associated with higher stage of disease. Extensive HCMV-pp65 expression was associated with shorter median overall survival than focal expression (39 versus 42.5 months, P = .03). At study closure, 58% of ovarian cancer patients with focal pp65 expression were alive versus 27% of patients with extensive pp65 expression (P = .03). Thus, HCMV proteins are detected at different levels in ovarian tumors and benign cystadenomas. Ovarian cancer patients with focal HCMV-pp65 expression in their tumors and high IgG levels against HCMV lived longer, highlighting a need for in-depth studies of the oncomodulatory role of HCMV in ovarian cancer.

CMV70-3P miRNA contributes to the CMV mediated glioma stemness and represents a target for glioma experimental therapy

Glioblastoma multiforme (GBM) is a rapidly progressive brain tumor with a median survival of 15–19 months. Therapeutic resistance and recurrence of the disease is attributed to cancer stem cells (CSC). Here, we report that CMV70-3P miRNA encoded by CMV increases GBM CSC stemness. Inhibition of CMV70-3P expression using oligo inhibitors significantly attenuated the ability of primary glioma cells to proliferate and form neurospheres. At the molecular level, we show that CM70-3P increases expression of cellular SOX2. Collectively, these findings indicate that CMV70-3P is a potential regulator of CMV- mediated glioma progression and cancer stemness.

Human cytomegalovirus may promote tumour progression by upregulating arginase-2

BACKGROUND

Both arginase (ARG2) and human cytomegalovirus (HCMV) have been implicated in tumorigenesis. However, the role of ARG2 in the pathogenesis of glioblastoma (GBM) and the HCMV effects on ARG2 are unknown. We hypothesize that HCMV may contribute to tumorigenesis by increasing ARG2 expression.

RESULTS

ARG2 promotes tumorigenesis by increasing cellular proliferation, migration, invasion and vasculogenic mimicry in GBM cells, at least in part due to overexpression of MMP2/9. The nor-NOHA significantly reduced migration and tube formation of ARG2-overexpressing cells. HCMV immediate-early proteins (IE1/2) or its downstream pathways upregulated the expression of ARG2 in U-251 MG cells. Immunostaining of GBM tissue sections confirmed the overexpression of ARG2, consistent with data from subsets of Gene Expression Omnibus. Moreover, higher levels of ARG2 expression tended to be associated with poorer survival in GBM patient by analyzing data from TCGA.

METHODS

The role of ARG2 in tumorigenesis was examined by proliferation-, migration-, invasion-, wound healing- and tube formation assays using an ARG2-overexpressing cell line and ARG inhibitor, N (omega)-hydroxy-nor-L-arginine (nor-NOHA) and siRNA against ARG2 coupled with functional assays measuring MMP2/9 activity, VEGF levels and nitric oxide synthase activity. Association between HCMV and ARG2 were examined in vitro with 3 different GBM cell lines, and ex vivo with immunostaining on GBM tissue sections. The viral mechanism mediating ARG2 induction was examined by siRNA approach. Correlation between ARG2 expression and patient survival was extrapolated from bioinformatics analysis on data from The Cancer Genome Atlas (TCGA).

CONCLUSIONS

ARG2 promotes tumorigenesis, and HCMV may contribute to GBM pathogenesis by upregulating ARG2.

Lack of cytomegalovirus detection in human glioma

Gliomas are the most common brain tumors and include a variety of histologic types and grades of malignancy. They arise from glial cells and represent approximately 70% of the primary brain tumors. According to the criteria of the World Health Organization (WHO), the majority of gliomas can be classified into four grades of malignancy (I-IV). Virus infection, especially by DNA viruses and retroviruses, which may cause insertion of viral DNA sequences into the host genome, often triggers the host defense mechanisms. Particularly, the DNA methylation machinery can be activated to cause the methylation of foreign movable viral sequences and, therefore, silence viral gene expression. Several studies have shown the presence of Human Cytomegalovirus (HCMV) in glioblastoma, suggesting that the virus may participate in tumor pathogenesis. But this relationship is controversial because many other studies did not detect HCMV in these tumors. This study aims to detect the presence of HCMV in several samples of human glioma (94 formalin-fixed, paraffin-embedded samples and 28 snap-frozen samples) by different sensitive techniques. We have been unable to detect HCMV DNA and proteins in glioma samples. Therefore, arguments used so far to conclude that HCMV is an oncomodulator virus in gliomas must be, in our view, seriously reconsidered.

Infections and cancer: the "fifty shades of immunity" hypothesis

BACKGROUND

Since the beginning of the twentieth century, infection has emerged as a fundamental aspect of cancer causation with a growing number of pathogens recognized as oncogenic. Meanwhile, oncolytic viruses have also attracted considerable interest as possible agents of tumor destruction.

DISCUSSION

Lost in the dichotomy between oncogenic and oncolytic agents, the indirect influence of infectious organisms on carcinogenesis has been largely unexplored. We describe the various ways - from functional aspects to evolutionary considerations such as modernity mismatches - by which infectious organisms could interfere with oncogenic processes through immunity. Finally, we discuss how acknowledging these interactions might impact public health approaches and suggest new guidelines for therapeutic and preventive strategies both at individual and population levels. Infectious organisms, that are not oncogenic neither oncolytic, may play a significant role in carcinogenesis, suggesting the need to increase our knowledge about immune interactions between infections and cancer.

Evaluation of JC and Cytomegalo Viruses in Glioblastoma Tissue

Glioblastoma multiforme (GBM) is the most aggressive of the gliomas, a collection of tumors arising from glia in the central nervous system. Possible associations between the human cytomegalovirus (HCMV) and the JC virus with GBM are now attracting interest. Our present aim was to investigate the prevalence of the two viruses in Iranian patients from Kerman’s cities in the south of Iran. In addition, the expression rates of pp65, large T antigen and p53 proteins were assessed and their relation with GBM evaluated using reverse transcription real time PCR (rReal Time PCR) . A total of 199 patients with GBM cancer were enrolled, with mean±SD ages of 50.0±19.5 and 50.7±19.6 years for males and females, respectively. The P53 rate was dramatically low suggesting an aetiological role,. Large T antigen expression was found in JC positive samples, while the PP65 antigen was observed in patients positive for CMV and JC . HCMV products and JC virus with oncogenic potential may induce the development of various tumors including glioblastomas. The JC virus produces an early gene product, T-antigen, which has the ability to associate with and functionally inactivate well-studied tumor suppressor proteins including p53 and pRB .

Human cytomegalovirus encoded chemokine receptor US28 activates the HIF-1α/PKM2 axis in glioblastoma cells

The human cytomegalovirus (HCMV) encoded chemokine receptor US28 promotes tumorigenesis through activation of various proliferative and angiogenic signaling pathways. Upon infection, US28 displays constitutive activity and signals in a G protein-dependent manner, hijacking the host's cellular machinery. In tumor cells, the hypoxia inducible factor-1α/pyruvate kinase M2 (HIF-1α/PKM2) axis plays an important role by supporting proliferation, angiogenesis and reprogramming of energy metabolism. In this study we show that US28 signaling results in activation of the HIF-1α/PKM2 feedforward loop in fibroblasts and glioblastoma cells. The constitutive activity of US28 increases HIF-1 protein stability through a Gαq-, CaMKII- and Akt/mTOR-dependent mechanism. Furthermore, we found that VEGF and lactate secretion are increased and HIF-1 target genes, glucose transporter type 1 (GLUT1) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), involved in glucose metabolism, are upregulated in US28 expressing cells. In addition, PKM2 is phosphorylated and found to be in a tumor-associated dimeric state upon US28 expression. Also in HCMV-infected cells HIF-1 activity is enhanced, which in part is US28-dependent. Finally, increased proliferation of cells expressing US28 is abolished upon inhibition of the HIF-1α/PKM2 cascade. These data highlight the importance of HIF-1α and PKM2 in US28-induced proliferation, angiogenesis and metabolic reprogramming.

To Infection and Beyond: The Multi-Pronged Anti-Cancer Mechanisms of Oncolytic Viruses

Over the past 1–2 decades we have witnessed a resurgence of efforts to therapeutically exploit the attributes of lytic viruses to infect and kill tumor cells while sparing normal cells. We now appreciate that the utility of viruses for treating cancer extends far beyond lytic cell death. Viruses are also capable of eliciting humoral and cellular innate and adaptive immune responses that may be directed not only at virus-infected cells but also at uninfected cancer cells. Here we review our current understanding of this bystander effect, and divide the mechanisms into lytic, cytokine, innate cellular, and adaptive phases. Knowing the key pathways and molecular players during virus infection in the context of the cancer microenvironment will be critical to devise strategies to maximize the therapeutic effects of oncolytic viroimmunotherapy.

Association between human cytomegalovirus and onset of epilepsy

OBJECTIVE

To explore the association between human cytomegalovirus (HCMV) and epilepsy.

METHODS

Epilepsy patients (n = 112) in neurology clinic of our hospital during January 2012 and December 2014 were allocated to the case groups, including intractable epilepsy group (n = 96) and non-intractable epilepsy group (n = 16). Healthy individual (n = 120) who received physical examination during the same period were allocated to the control group. The expression of serum HCMV late gene pp67-RNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of serum HCMV immunoglobulin G (IgG), immunoglobulin M (IgM) and interleukin-6 (IL-6) were detected by enzyme-linked immunosorbent assay (ELISA). Serum hypersensitive c-reactive protein (hs-CRP) was detected by latex-enhanced immunoturbidimetry. The electroencephalogram (EEG) of refractory epilepsy group, non-refractory epilepsy group and control group were recorded.

RESULTS

The expression of pp67-mRNA was significantly higher in intractable epilepsy group than non-intractable epilepsy group (P < 0.05) and control group (P < 0.001). The HCMV-IgG positive rate and HCMV-IgM positive rate were significantly higher in intractable epilepsy group than control group (both P < 0.001). The HCMV-IgM positive rate was significantly higher in intractable epilepsy group than non-intractable epilepsy group (P < 0.001). The HCMV-IgM positive rate was significantly higher in non-intractable epilepsy group than control group (P < 0.001). The hs-CRP and IL-6 levels presented descending trends respectively in intractable epilepsy group, non-intractable epilepsy group and control group (all P < 0.001).

CONCLUSION

HCMV was prominently expressed in epilepsy and might contribute to the development of epilepsy.

Serological and viraemic status of human cytomegalovirus infection in patients with colorectal cancer is not correlated with viral replication and transcription in tumours

Colorectal cancer (CRC) is amongst the leading causes of cancer-related mortality worldwide. Emerging evidence suggests that human cytomegalovirus (HCMV) exists in the tumour tissue of CRC and is associated with disease outcome. To study whether tumoral HCMV is related to viral reactivation in blood, tumour specimens and pre- and post-operative blood samples from CRC patients were collected prospectively. PCR and quantitative PCR were performed to detect HCMV DNA. HCMV IgG and IgM antibodies were measured using a microparticle enzyme immunoassay. Transcription of a spliced HCMV UL73 gene transcript was analysed by quantitative reverse transcription PCR. HCMV was detected in 42.2% (35/83) of the tumour samples, with a low median viral load (30.08, range 2.33-5704 copies per 500  ng genomic DNA). The vast majority (80/81, 98.8%) of the CRC patients were seropositive for HCMV IgG. HCMV DNA was positive in 11.3% (22/194) of the pre-operative and 8.9% (15/168) of the post-operative blood samples. However, presence of HCMV and its viral load in tumours were not associated with the detection or viral loads in blood samples. About 26.67% (8/30) of the HCMV-positive tumours with available RNA had detectable viral UL73 transcripts, whilst none of the blood samples were positive for viral RNA (P < 0.0001). Therefore, presence of HCMV in tumours does not correlate with the serological or viraemic status of CRC patients. Active viral gene transcription occurred in the tumour but not in the blood of CRC patients. HCMV reactivation in CRC patients is possibly due to virus-cancer interactions in the CRC tumour microenvironment.

Is CMV a target in pediatric glioblastoma? Expression of CMV proteins, pp65 and IE1-72 and CMV nucleic acids in a cohort of pediatric glioblastoma patients

While the 5-year overall survival is better in pediatric than in adult patients diagnosed with glioblastoma (GBM), outcomes in children remain very poor. Understanding the mechanisms of tumorigenesis and tumor propagation can identify therapeutic targets to improve these outcomes. Human cytomegalovirus (CMV) proteins and nucleic acids are present in the majority of adult GBM. Indeed, CMV is emerging as a potential glioma-associated target for anti-CMV agents and cellular therapeutics. Furthermore, CMV appears to contribute to GBM’s malignant phenotype, although its role in tumorigenesis is less certain. In this cohort of 25 serially diagnosed pediatric GBMs, the largest described cohort to date, we used immunohistochemical staining and in situ hybridization to show the presence of CMV antigens pp65 and IE1-72 as well as CMV nucleic acids, respectively. Our cohort indicated either CMV antigen pp65 or IE1-72 was present in approximately 67 % of pediatric GBM samples. The majority of samples stained positive for either CMV antigen showing a cytoplasmic pattern in 25-50 % of cells within the sample at a moderate intensity, while a few samples showed nuclear staining and higher grade/intensity. Of 16 samples where in situ hybridization was performed, 13 (81 %) showed specific staining using a CMV genome specific probe cocktail. ISH positive samples showed high concordance with being pp65 or IE1-72 positive. These findings, paired with the association of CMV expression with poor prognosis and overall survival, indicate the need to further investigate how these antigens are promoting tumor growth and preventing cell death. Also, the expression of these antigens in a majority of tumor tissues should be considered for immunotherapeutic targets in cases of pediatric GBM.

Gene co-expression network and function modules in three types of glioma

The aim of the present study was to identify the disease‑associated genes and their functions involved in the development of three types of glioma (astrocytoma, glioblastoma and oligodendroglioma) with DNA microarray technology, and to analyze their differences and correlations. First, the gene expression profile GSE4290 was downloaded from the Gene Expression Omnibus database, then the probe‑level data were pre‑processed and the differentially expressed genes (DEGs) were identified with limma package in R language. Gene functions of the selected DEGs were further analyzed with the Database for Annotation, Visualization and Integrated Discovery. After the co‑expression network of DEGs was constructed by Cytoscape, the functional modules were mined and enrichment analysis was performed, and then the similarities and differences between any two types of glioma were compared. A total of 1151 genes between normal and astrocytoma tissues, 684 genes between normal and malignant glioma tissues, and 551 genes between normal and oligodendroglioma tissues were filtered as DEGs, respectively. By constructing co‑expression networks of DEGs, a total of 77232, 455 and 987 interactions were involved in the differentially co‑expressed networks of astrocytoma, oligodendroglioma and glioblastoma, respectively. The functions of DEGs were consistent with the modules in astrocytoma, glioblastoma and oligodendroglioma, which were mainly enriched in neuron signal transmission, immune responses and synthesis of organic acids, respectively. Model functions of astrocytoma and glioblastoma were similar (mainly related with immune response), while the model functions of oligodendroglioma differed markedly from that of the other two types. The identification of the associations among these three types of glioma has potential clinical utility for improving the diagnosis of different types of glioma in the future. In addition, these results have marked significance in studying the underlying mechanisms, distinguishing between normal and cancer tissues, and examining novel therapeutic strategies for patients with glioma.

Overexpression of enhancer of zeste human homolog 2 (EZH2) gene in human cytomegalovirus positive glioblastoma multiforme tissues

Glioblastoma multiforme (GBM) is considered to be one of the most invasive human cancers, characterized by a high mortality rate and an average survival is <1 year. These tumors are highly aggressive and insensitive to conventional radio and chemotherapy. An interesting aspect of glioblastoma is the association of active human cytomegalovirus (HCMV) infection, which is evident by the presence of viral DNA, mRNA and protein level in most glioblastoma tissues. Although the presence of the HCMV infection in glioblastoma is well established, but the oncomodulatory role of HCMV is not defined yet. Enhancer of zeste human homolog 2 (EZH2) is a key protein of the polycomb repressive complex 2, epigenetic gene silencers. There have been several reports that EZH2 activity is essential in GBM pathogenesis. In our previous research, we have found a high rate of HCMV infection in a cohort of Iranian glioblastoma patients. In this study, we investigated the expression of EZH2 in HCMV-negative versus HCMV-positive GBM tissues in comparison to non-tumor tissues. The level of expression was determined by real time PCR and the differences were calculated using the Livac or 2(-ΔΔCt) and analysis of variance (ANOVA). Relative expression of EZH2 in HCMV-negative glioblastoma tissues were increased 6.053-fold compared to non-neoplastic brain tissues, while EZH2 gene expression was increased 41.098-fold in HCMV-positive glioblastoma tissues. ANOVA test showed that there is a significant difference in EZH2 expression between normal brain tissue, HCMV-negative and HCMV-positive glioblastoma tumors (p value = 0.0001). Our data indicate that EZH2 expression can be considered a risk factor in glioblastoma and EZH2 inhibitors may serve as potential new treatment in glioblastoma. This would be an interesting new field to investigate in more detail.

Human cytomegalovirus tegument protein pp65 is detected in all intra- and extra-axial brain tumours independent of the tumour type or grade

Human cytomegalovirus (HCMV) has been indicated being a significant oncomodulator. Recent reports have suggested that an antiviral treatment alters the outcome of a glioblastoma. We analysed the performance of commercial HCMV-antibodies applying the immunohistochemical (IHC) methods on brain sample obtained from a subject with a verified HCMV infection, on samples obtained from 14 control subjects, and on a tissue microarray block containing cores of various brain tumours. Based on these trials, we selected the best performing antibody and analysed a cohort of 417 extra- and intra-axial brain tumours such as gliomas, medulloblastomas, primary diffuse large B-cell lymphomas, and meningiomas. HCMV protein pp65 immunoreactivity was observed in all types of tumours analysed, and the IHC expression did not depend on the patient's age, gender, tumour type, or grade. The labelling pattern observed in the tumours differed from the labelling pattern observed in the tissue with an active HCMV infection. The HCMV protein was expressed in up to 90% of all the tumours investigated. Our results are in accordance with previous reports regarding the HCMV protein expression in glioblastomas and medulloblastomas. In addition, the HCMV protein expression was seen in primary brain lymphomas, low-grade gliomas, and in meningiomas. Our results indicate that the HCMV protein pp65 expression is common in intra- and extra-axial brain tumours. Thus, the assessment of the HCMV expression in tumours of various origins and pathologically altered tissue in conditions such as inflammation, infection, and even degeneration should certainly be facilitated.

Glioblastoma multiforme - an overview

Glioblastoma multiforme is a central nervous system tumor of grade IV histological malignancy according to the WHO classification. Over 90% of diagnosed glioblastomas multiforme cases are primary gliomas, arising from normal glial cells through multistep oncogenesis. The remaining 10% are secondary gliomas originating from tumors of lower grade. These tumors expand distinctly more slowly. Although genetic alterations and deregulations of molecular pathways leading to both primary and secondary glioblastomas formation differ, morphologically they do not reveal any significant differences. Glioblastoma is a neoplasm that occurs spontaneously, although familial gliomas have also been noted. Caucasians, especially those living in industrial areas, have a higher incidence of glioblastoma. Cases of glioblastoma in infants and children are also reported. The participation of sex hormones and viruses in its oncogenesis was also suggested. Progression of glioblastoma multiforme is associated with deregulation of checkpoint G1/S of a cell cycle and occurrence of multiple genetic abnormalities of tumor cells. Metastases of glioblastoma multiforme are rarely described. Treatment of glioblastoma multiforme includes tumor resection, as well as radiotherapy and chemotherapy. Drugs inhibiting integrin signaling pathways and immunotherapy are also employed. Treatment modalities and prognosis depend on the tumor localization, degree of its malignancy, genetic profile, proliferation activity, patient's age and the Karnofsky performance scale score. Although the biology of glioblastoma multiforme has recently been widely investigated, the studies summarizing the knowledge of its development and treatment are still not sufficient in terms of comprehensive brain tumor analysis.

Immunoglobulin genes implicated in glioma risk

Both genetic and environmental factors are thought to be causal in gliomagenesis. Several genes have been implicated in glioma development, but the putative role of a major immunity-related gene complex member, immunoglobulin heavy chain γ (IGHG) has not been evaluated. Prior observations that IGHG-encoded γ marker (GM) allotypes exhibit differential sensitivity to an immunoevasion strategy of cytomegalovirus, a pathogen implicated as a promoter of gliomagenesis, has lead us to hypothesize that these determinants are risk factors for glioma. To test this hypothesis, we genotyped the IGHG locus comprising the GM alleles, specifically GM alleles 3 and 17, of 120 glioma patients and 133 controls via TaqMan® genotyping assay. To assess the associations between GM genotypes and the risk of glioma, we applied an unconditional multivariate logistic regression analysis adjusted for potential confounding variables. In comparison to subjects who were homozygous for the GM 17 allele, the GM 3 homozygotes were over twice as likely, and the GM 3/17 heterozygotes were over three times as likely, to develop glioma. Similar results were achieved when analyzed by combining the data corresponding to alleles GM 3 and GM 3/17 in a dominant model. The GM 3/17 genotype and the combination of GM 3 and GM 3/17 were found to be further associated with over 3 times increased risk for high-grade astrocytoma (grades III-IV). Allele frequency analyses also showed an increased risk for gliomas and high-grade astrocytoma in association with GM 3. Our findings support the premise that the GM 3 allele may present risk for the development of glioma, possibly by modulating immunity to cytomegalovirus.

The role of extracellular vesicles in the progression of neurodegenerative disease and cancer

Extracellular vesicles (EVs) are released from many cell types, including normal and pathological cells, and range from 30 to 1000 nm in size. Once thought to be a mechanism for discarding unwanted cellular material, EVs are now thought to play a role in intercellular communication. Evidence is accruing that EVs are capable of carrying mRNAs, miRNAs, noncoding RNAs, and proteins, including those associated with neurodegenerative diseases and cancer, which may be exchanged between cells. For this reason, neurodegenerative diseases and cancers may share a common mechanism of disease spread via EVs. Understanding the role EVs play in disease initiation and progression will aid in the discovery of new clinically relevant biomarkers and the development of better targeted molecular and biological therapies.

Current vaccine trials in glioblastoma: a review

Glioblastoma (GBM) is the most common primary brain tumor, and despite aggressive therapy with surgery, radiation, and chemotherapy, average survival remains at about 1.5 years. The highly infiltrative and invasive nature of GBM requires that alternative treatments for this disease be widespread and targeted to tumor cells. Immunotherapy in the form of tumor vaccines has the potential to meet this need. Vaccines against GBM hold the promise of triggering specific and systemic antitumor immune responses that may be the key to eradicating this unrelenting cancer. In this review, we will discuss past and present clinical trials of various GBM vaccines and their potential impact on the future care of GBM patients. There have been many promising phase I and phase II GBM vaccine studies that have led to ongoing and upcoming phase III trials. If the results of these randomized trials show a survival benefit, immunotherapy will become a standard part of the treatment of this devastating disease.

Does the existence of HCMV components predict poor prognosis in glioma?

Human cytomegalovirus (HCMV) has been associated with malignant gliomas. The objective of the present study was to further investigate the existence and prognostic value of HCMV components in gliomas. Using immunohistochemical staining, HCMV proteins IE1-72 and pp65 were examined in 67 glioma specimens of various histologic grades, in comparison to 6 -control brain tissue samples. The HCMV DNA was measured in both the tumor tissues and the peripheral blood of the patients, using nested PCR. Kaplan-Meier analysis and Cox proportional hazards models were used to analyzed the prognostic value of HCMV components in glioma tissues. IE1-72 was detected in 76.1% (51/67) of glioma tissues, and pp65 was detected in 65.7% (44/67) of glioma tissues. HCMV DNA was detected in 52.2% (35/67) of glioma tissues and 29.9% (20/67) of peripheral blood samples of glioma patients. These HCMV components were not detected in control brain tissue. However, the existence of HCMV components showed no significant correlation with the prognosis of glioma patients. Our results demonstrate that although HCMV proteins and nucleic acids are present in gliomas, they do not correlate with the prognosis. The role of HCMV in gliomas needs to be carefully interpreted.

A novel DDB2-ATM feedback loop regulates human cytomegalovirus replication

Human cytomegalovirus (HCMV) genome replication requires host DNA damage responses (DDRs) and raises the possibility that DNA repair pathways may influence viral replication. We report here that a nucleotide excision repair (NER)-associated-factor is required for efficient HCMV DNA replication. Mutations in genes encoding NER factors are associated with xeroderma pigmentosum (XP). One of the XP complementation groups, XPE, involves mutation in ddb2, which encodes DNA damage binding protein 2 (DDB2). Infectious progeny virus production was reduced by >2 logs in XPE fibroblasts compared to levels in normal fibroblasts. The levels of immediate early (IE) (IE2), early (E) (pp65), and early/late (E/L) (gB55) proteins were decreased in XPE cells. These replication defects were rescued by infection with a retrovirus expressing DDB2 cDNA. Similar patterns of reduced viral gene expression and progeny virus production were also observed in normal fibroblasts that were depleted for DDB2 by RNA interference (RNAi). Mature replication compartments (RCs) were nearly absent in XPE cells, and there were 1.5- to 2.0-log reductions in viral DNA loads in infected XPE cells relative to those in normal fibroblasts. The expression of viral genes (UL122, UL44, UL54, UL55, and UL84) affected by DDB2 status was also sensitive to a viral DNA replication inhibitor, phosphonoacetic acid (PAA), suggesting that DDB2 affects gene expression upstream of or events associated with the initiation of DNA replication. Finally, a novel, infection-associated feedback loop between DDB2 and ataxia telangiectasia mutated (ATM) was observed in infected cells. Together, these results demonstrate that DDB2 and a DDB2-ATM feedback loop influence HCMV replication.

Carcinogenic viruses and solid cancers without sufficient evidence of causal association

Viral infections are important risk factors for tumor development in humans. Selected types of cancers, either lymphomas or carcinomas, for which there is sufficient evidence in humans of a causal association with specific viruses, have been identified. Experimental and clinical data on the possible association of other tumor types and carcinogenic viruses are presently controversial. In this article, we review the current evidence on the relationship between breast, colorectal and lung cancers and carcinogenic viruses. The majority of the publications reviewed do not provide definitive evidence that the viruses studied are associated with breast, colon and lung cancers. However, since this association may be clinically relevant for some tumor subtypes (i.e., lung cancer and papillomaviruses), there is an urgent need for further investigation on this topic. Using innovative laboratory techniques for viral detection on well-defined tumor types, National and International networks against cancer should encourage and organize concerted research programs on viruses and solid cancer association.

Saturated very long chain fatty acids are required for the production of infectious human cytomegalovirus progeny

Human cytomegalovirus hijacks host cell metabolism, increasing the flux of carbon from glucose to malonyl-CoA, the committed precursor to fatty acid synthesis and elongation. Inhibition of acetyl-CoA carboxylase blocks the production of progeny virus. To probe further the role of fatty acid metabolism during infection, we performed an siRNA screen to identify host cell metabolic enzymes needed for the production of infectious cytomegalovirus progeny. The screen predicted that multiple long chain acyl-CoA synthetases and fatty acid elongases are needed during infection, and the levels of RNAs encoding several of these enzymes were upregulated by the virus. Roles for acyl-CoA synthetases and elongases during infection were confirmed by using small molecule antagonists. Consistent with a role for these enzymes, mass spectrometry-based fatty acid analysis with¹³C-labeling revealed that malonyl-CoA is consumed by elongases to produce very long chain fatty acids, generating an approximately 8-fold increase in C26-C34 fatty acid tails in infected cells. The virion envelope was yet further enriched in C26-C34 saturated fatty acids, and elongase inhibitors caused the production of virions with lower levels of these fatty acids and markedly reduced infectivity. These results reveal a dependence of cytomegalovirus on very long chain fatty acid metabolism.

Herpes viruses modulate cellular pathways to generate the building blocks that are necessary for their replication. Human cytomegalovirus alters metabolism of infected cells and causes a dramatic increase in lipid biosynthesis. We have investigated the role of lipid pathways in the viral life cycle and discovered that the virus requires several host enzymes that are responsible for the synthesis of very long chain fatty acids. Interestingly, very long chain fatty acids are substantially increased in the lipids of infected cells and saturated forms of these fatty acids are selectively incorporated into the envelope of the virus. Drugs that inhibit the synthesis of very long chain fatty acids generate virus particles with reduced infectivity. The discovery that human cytomegalovirus depends on the production of particular fatty acids furthers our understanding of virus-host cell interaction and suggests potential novel strategies for antiviral therapies.

Human cytomegalovirus infection enhances NF-κB/p65 signaling in inflammatory breast cancer patients

Human Cytomegalovirus (HCMV) is an endemic herpes virus that re-emerges in cancer patients enhancing oncogenic potential. Recent studies have shown that HCMV infection is associated with certain types of cancer morbidity such as glioblastoma. Although HCMV has been detected in breast cancer tissues, its role, if any, in the etiology of specific forms of breast cancer has not been investigated. In the present study we investigated the presence of HCMV infection in inflammatory breast cancer (IBC), a rapidly progressing form of breast cancer characterized by specific molecular signature. We screened for anti-CMV IgG antibodies in peripheral blood of 49 non-IBC invasive ductal carcinoma (IDC) and 28 IBC patients. In addition, we screened for HCMV-DNA in postsurgical cancer and non-cancer breast tissues of non-IBC and IBC patients. We also tested whether HCMV infection can modulate the expression and activation of transcriptional factor NF-κB/p65, a hallmark of IBC. Our results reveal that IBC patients are characterized by a statistically significant increase in HCMV IgG antibody titers compared to non-IBC patients. HCMV-DNA was significantly detected in cancer tissues than in the adjacent non-carcinoma tissues of IBC and IDC, and IBC cancer tissues were significantly more infected with HCMV-DNA compared to IDC. Further, HCMV sequence analysis detected different HCMV strains in IBC patients tissues, but not in the IDC specimens. Moreover, HCMV-infected IBC cancer tissues were found to be enhanced in NF-κB/p65 signaling compared to non-IBC patients. The present results demonstrated a correlation between HCMV infection and IBC. Etiology and causality of HCMV infection with IBC now needs to be rigorously examined.

Anti-human-cytomegalovirus immunoglobulin G levels in glioma risk and prognosis

The role of human cytomegalovirus (HCMV) in glioma development and progression remains controversial. The purpose of our study was to assess the potential associations between anti-HCMV antibodies (immunoglobulin G [IgG] and immunoglobulin M [IgM]) and glioma risk and prognosis using data from the Harris County Case–Control Study. Multivariable logistic regression models were utilized to estimate odds ratios and 95% confidence intervals (CI) for the associations between glioma status and antibody levels among glioma cases (n = 362) and cancer-free controls (n = 462). Hazard ratios and 95% CIs were calculated using Cox proportional hazards regression, adjusting for age, race, and sex, to determine if antibody levels were associated with survival over time among cases. Among IgG-positive participants, increasing anti-HCMV IgG levels were associated with decreasing glioma risk (P for trend = 0.0008), and those with the lowest level of anti-HCMV IgG (<10 U/mL) had the highest glioma risk, controlling for age, sex, and race/ethnicity (OR: 2.51, 95% CI: 1.42–4.43). Antibody levels were not associated with survival among glioma cases. Our study contributes new evidence toward the potential importance of the direct and indirect effects of HCMV infection in gliomagenesis.

Molecular mechanisms deployed by virally encoded G protein-coupled receptors in human diseases

G protein-coupled receptors (GPCRs) represent the largest family of cell surface molecules involved in signal transduction. Surprisingly, open reading frames for multiple GPCRs were hijacked in the process of coevolution between Herpesviridae family viruses and their human and mammalian hosts. Virally encoded GPCRs (vGPCRs) evolved as parts of viral genomes, and this evolution allowed the power of host GPCR signaling circuitries to be harnessed in order to ensure viral replicative success. Phylogenetically, vGPCRs are distantly related to human chemokine receptors, although they feature several unique characteristics. Here, we describe the molecular mechanisms underlying vGPCR-mediated viral pathogenesis. These mechanisms include constitutive activity, aberrant coupling to human G proteins and β-arrestins, binding and activation by human chemokines, and dimerization with other GPCRs expressed in infected cells. The likely structural basis for these molecular events is described for the two closest viral homologs of human GPCRs. This information may aid in the development of novel targeted therapeutic strategies against viral diseases.

Structural Diversity in Conserved Regions Like the DRY-Motif among Viral 7TM Receptors-A Consequence of Evolutionary Pressure?

Several herpes- and poxviruses have captured chemokine receptors from their hosts and modified these to their own benefit. The human and viral chemokine receptors belong to class A 7 transmembrane (TM) receptors which are characterized by several structural motifs like the DRY-motif in TM3 and the C-terminal tail. In the DRY-motif, the arginine residue serves important purposes by being directly involved in G protein coupling. Interestingly, among the viral receptors there is a greater diversity in the DRY-motif compared to their endogenous receptor homologous. The C-terminal receptor tail constitutes another regulatory region that through a number of phosphorylation sites is involved in signaling, desensitization, and internalization. Also this region is more variable among virus-encoded 7TM receptors compared to human class A receptors. In this review we will focus on these two structural motifs and discuss their role in viral 7TM receptor signaling compared to their endogenous counterparts.

Humoral immunity to cytomegalovirus and chronic graft-versus-host disease

Human cytomegalovirus (HCMV) is an important cause of morbidity and mortality in patients with chronic graft-versus-host disease (cGVHD), but the underlying mechanisms are not understood. The aim of this investigation was to determine whether humoral immune responses to the HCMV antigens were quantitatively different in hematopoietic cell transplant (HCT) recipients who developed cGVHD from those who did not. Antibodies to HCMV and its proteins UL94 and UL70 were quantitated in 79 cGVHD and 30 non-cGVHD patients by enzyme-linked immunosorbent assays (ELISAs). Mean levels of antibodies to the whole HCMV and to its protein UL94 were not significantly different between the cGVHD and the non-cGVHD subjects. However, the levels of antibodies to HCMV UL70 were significantly higher in non-cGVHD subjects than in those with cGVHD (20.91±15.63 versus 15.00±10.35 ng/mL; p=0.03). This suggests that anti-UL70 antibodies might play a protective role in the development of cGVHD.

Is human cytomegalovirus a target in cancer therapy?

Human cytomegalovirus (HCMV) is a herpesvirus that is prevalent in the human population. HCMV has recently been implicated in different cancer forms where it may provide mechanisms for oncogenic transformation, oncomodulation and tumour cell immune evasion. Moreover, antiviral treatment against HCMV has been shown to inhibit tumour growth in preclinical models. Here we describe the possible involvement of HCMV in cancer and discuss the potential molecular impact expression of HCMV proteins have on tumour cells and the surrounding tumour microenvironment.

Generation of polyclonal CMV-specific T cells for the adoptive immunotherapy of glioblastoma

Glioblastoma (GBM) is the most common primary brain cancer in adults and is virtually incurable. Recent studies have shown that cytomegalovirus (CMV) is present in majority of GBMs. To evaluate whether the CMV antigens pp65 and IE1, which are expressed in GBMs, could be targeted by CMV-specific T cells, we measured the frequency of T cells targeting pp65 and IE1 in the peripheral blood of a cohort of 11 sequentially diagnosed CMV-seropositive GBM patients, and evaluated whether it was feasible to expand autologous CMV-specific T cells for future clinical studies. All 11 CMV-seropositive GBM patients had T cells specific for pp65 and IE1 in their peripheral blood assessed by IFNγ enzyme-linked immunospot assay. However, the precursor frequency of pp65-specific T cells was decreased in comparison with healthy donors (P=0.001). We successfully reactivated and expanded CMV-specific T cells from 6 out of 6 GBM patients using antigen-presenting cells transduced with an adenoviral vector encoding pp65 and IE1. CMV-specific T-cell lines contained CD4 as well as CD8 T cells, recognized pp65 and IE1 targets and killed CMV-infected autologous GBM cells. Infusion of such CMV-specific T-cell lines may extend the benefits of T-cell therapy to patients with CMV GBMs.