[Fractionated conformal stereotactic irradiation of recurrent sacral tumour. Case report and first description of the method in Hungary]. / Recidív sacrumdaganat frakcionált, konformális sztereotaxiás sugárkezelése. Esetismertetés és a módszer elsõ hazai leírása.

Non-invasive procedures completing traditional surgical treatment play an increasing role in the management of central nervous system malignancies. Conformal stereotactic irradiation (radiosurgery) has become a routine method in intracranial malignancies. However, application of this modality in tumours of the spinal cord and spinal column is much more difficult to perform. It is because extracranial organs can be only inaccurately fixed, and radio-sensitivity of the spinal cord and risks of radionecrosis with ensuing paraplegia are high. A recurrent sacrum chordoma treated by means of this modality - first reported in Hungary - has been chosen for case presentation as the criteria for radiotherapy such as high dose to target volume, minimal dose to neighbouring structures highly sensitive to radiation are best met in these tumours by means of conformal stereotactic radiotherapy. On the basis of further 13 extracranial cases treated with this method one can conclude that high precision stereotactic conformal radiotherapy offers up-grade to traditional radiotherapy despite the fact that it is a time-consuming procedure. The oncological efficiency, the reduced risks of side effects and the improved quality of life due to this treatment modality compensate duly for the increased labour input.

Expression Levels of GHRH-Receptor, pAkt and Hsp90 Predict 10-Year Overall Survival in Patients with Locally Advanced Rectal Cancer.

BACKGROUND: Rectal cancer constitutes nearly one-third of all colorectal cancer diagnoses, and certain clinical and molecular markers have been studied as potential prognosticators of patient survival. The main objective of our study was to investigate the relationship between the expression intensities of certain proteins, including growth-hormone-releasing hormone receptor (GHRH-R), Hsp90, Hsp16.2, p-Akt and SOUL, in specimens of locally advanced rectal cancer patients, as well as the time to metastasis and 10-year overall survival (OS) rates. We also investigated whether these outcome measures were associated with the presence of other clinical parameters. METHODS: In total, 109 patients were investigated retrospectively. Samples of pretreatment tumors were stained for the proteins GHRH-R, Hsp90, Hsp16.2, p-Akt and SOUL using immunhistochemistry methods. Kaplan-Meier curves were used to show the relationships between the intensity of expression of biomarkers, clinical parameters, the time to metastasis and the 10-year OS rate. RESULTS: High levels of p-Akt, GHRH-R and Hsp90 were associated with a significantly decreased 10-year OS rate (p = 0.001, p = 0.000, p = 0.004, respectively) and high expression levels of p-Akt and GHRH-R were correlated with a significantly shorter time to metastasis. Tumors localized in the lower third of the rectum were linked to both a significantly longer time to metastasis and an improved 10-year OS rate. CONCLUSIONS: Hsp 90, pAkt and GHRH-R as well as the lower-third localization of the tumor were predictive of the 10-year OS rate in locally advanced rectal cancer patients. The GHRH-R and Hsp90 expression levels were independent prognosticators of OS. Our results imply that GHRH-R could play a particularly important role both as a molecular biomarker and as a target for the anticancer treatment of advanced rectal cancer.

Histological examination of vascular lesions caused by stent implantation in humans and in comparative experimental animal model.

A comparative analysis of human and experimental animal (canine) tissues was performed to characterize and describe cellular and histological responses during the processes of newly forming intravascular tissues after stent implantation. Routine histological and immunohistochemical evaluation of 20 human samples and 9 samples from animal models were used one day, one week and one month after the stent implantation. After one day of implantation, there was no difference between the human and canine peripheral arteries, suggesting a similar cellular and histological response in the early phase. In contrast, after one week of implantation, during the proliferative phase the repairing human tissue showed less intensive production of inflammatory cells and more intensive increase in number of vascular cells than did the canine model. In addition, cellular changes normally restituted by the end of one month in canine peripheral arteries, but vascular cells persisted in human atherosclerotic arteries. In conclusion, results of this study suggest differences in both phases of vascular repair in the post-stented period, because both proliferative and regressive phases showed histological differences in canine and human samples. In canine, the restitution of vascular wall was completed by the end of first month but persistent vascular cell proliferation was visible in the human peripheral arteries. It can be suggested that delayed cellular response might indicate restenosis but also can be considered considered as a progression of the original arterial disease.

Upregulation of transient receptor potential vanilloid type-1 receptor expression in oral lichen planus.

OBJECTIVES: Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa. Its etiology is still unclear. Neurogenic components might contribute to the inflammatory process. The oral mucosa is richly innervated by sensory fibers. Mediators secreted by inflammatory cells activate sensory nerves via transient receptor potential vanilloid receptor 1 (TRPV1) and lead to the release of neuropeptides. So far, TRPV1 receptor expression was detected on neurons. Only recently, TRPV1 receptors were identified in nonneuronal tissues. The aim of the present study was to detect the presence of TRPV1 receptors and peripheral expression of receptor mRNA in normal oral mucosa and mucous membranes from OLP patients. METHODS: Presence of TRPV1 receptor proteins in the mucosal tissue was assessed by immunohistochemistry. Expression of TRPV1 receptor mRNA was determined by quantitative RT-PCR. RESULTS: We provided qualitative and quantitative immunohistochemical evidence that TRPV1 receptors are present in normal human oral mucosa and that their expression is increased in OLP. The number of immunopositive cells was elevated in the epithelium, and vascular endothelial cells, lymphocytes and fibroblasts of the subepithelium were also labeled in samples obtained from OLP patients. The local expression of nonneuronal TRPV1 receptors was proven at mRNA level using quantitative real-time RT-PCR. CONCLUSIONS: Since the number of TRPV1 receptor-positive nonneural cells is increased in inflammatory conditions, we hypothesize that TRPV1-receptor-mediated processes might play role in the pathogenesis of OLP.

Invariant Valpha7.2-Jalpha33 TCR is expressed in human kidney and brain tumors indicating infiltration by mucosal-associated invariant T (MAIT) cells.

The anti-tumor response of human invariant NKT (NKT) cells is well established. A novel T cell subset, mucosal-associated invariant T (MAIT) cells, possesses similar regulatory properties to NKT cells in autoimmune models and disease. Here, we examined the clonality of four T cell subsets expressing invariant alphaTCR, including Valpha7.2-Jalpha33 of MAIT cells, in 19 kidney and brain tumors. The MAIT clonotype was identified and co-expressed with NKT clonotype in half of the tumors. In contrast, two other invariant T cell clonotypes (Valpha4 and Valpha19) were not present in tumors. Such tumors also expressed Vbeta2 and Vbeta13, the restricted TCRbeta chain of MAIT cells and the antigen-presenting molecule MR1. A high percentage of infiltrating T cells was CD8+ and expressed HLA-DR suggesting activation. Although the MAIT alphaTCR was identified in both peripheral CD56+ and CD56- subsets, infiltrating lymphocytes were CD56 negative. The clonal presence of MAIT cells in tumors correlated with the expression of pro-inflammatory cytokines but no IL-4, IL-5 and IL-10, suggesting that a pro-inflammatory subset of human MAIT cells may exist. Our data imply that a CD56- subset of MAIT cells may participate in tumor immune responses similarly to NKT cells.

[Surgical treatment of primary leiomyosarcoma of the inferior vena cava]. / Primer vena cava inferior leiomyosarcoma (VCI-LMS) sebészi kezelése.

CASE REPORT: pLMS in the wall of the inferior vena cava is an extremely rare form of retroperitoneal malignancies. A case in a young female patient is presented; clinical symptoms, pre- and postoperative diagnosis and surgical treatment are discussed. A retroperitoneal mass detected by imaging was found to be a large tumor mass located at the middle segment of the IVC on exploration. The tumour was successfully excised and the IVC was reconstructed with a synthetic graft. Eight years later, this patient needed a repeat surgery due to local recurrence. This time tumour was attached to the left renal vein. A re-resection of the IVC was performed with subsequent synthetic graft reconstruction and the distal end of the left renal vein was reimplanted into a lower segment of IVC. DISCUSSION: Primary leiomyosarcoma of the inferior vena cava (pLMS-IVC) is an extremely rare form of retroperitoneal malignancies. The tumour arises from the medial layer of the venous wall and can grow either intraluminally, or extraluminally or in both directions, as well. It can be localized in the first segment of IVC (above the hepatic veins), in the second segment between hepatic and renal veins and finally in the third segment between the right common iliac vein and renal veins. Therefore, the tumour can infiltrate both hepatic and/or renal vessels. Upper segment tumours can cause Budd-Chiari syndrome (hepatomegaly, abdominal pain, jaundice and ascites) with a bad prognosis. Middle segment tumours usually present with right upper quadrant pain, or may mimic biliary tract disease with a much better prognosis. Accumulating experience suggests that radio-chemotherapy alone seems to be less effective than "en bloc" resection with clear margins including loco-regional lymph nodes. Therefore, our choice of treatment was the latter. Although radical resection can be carried out in most of cases, 50% of patients develop a late recurrence yet.

[Neoadjuvant radiochemotherapy in the treatment of locally advanced rectal tumors]. / Neoadjuváns radiokemoterápia a lokoregionálisan elorehaladott rectumtumorok ellátásában.

We investigated the response rate and side effects of simultaneous, neoadjuvant radiochemotherapy (RCT) in locally advanced rectal cancer. Between 2005 and 2007, we treated 112 patients in stage II-III rectal carcinoma at the Institute of Oncotherapy, University of Pécs. For staging abdomino-pelvic CT (112) and transrectal US (49) or pelvic MR (10), or PET-CT (1) was performed. Radiation therapy was delivered with 3D CRT-based technique using belly-board with 18 MV photon energy, while patients in prone position. A total dose of 45 Gy (single dose 1.8 Gy) was delivered to the tumor and the pelvic lymph nodes. 5-FU and Ca-folinate was administered concomitantly in the 1st and 5th week of radiotherapy. Four weeks after delivering neoadjuvant RCT the patients' control CT was evaluated according to RECIST criteria. RCT was followed by surgery in 6-9 weeks. We graded the histology using the Mandard regression score system. Side effects were registered using CTCAE v 3.0. Grade 1, 2 or 3 acute gastrointestinal toxicity occurred in 12%, grade 3 hematological toxicity in 9.5% of the patients. The response rate determined by using control CT was 64.85%. According to the Mandard regression score, TRG1 occurred in 15%, TRG2 in 30.4%, TRG3 in 28%, TRG4 in 24% and TRG5 in 2.6% of the cases. Radical surgery was performed in 89 cases, 72 with R0 resection. By assessing the histological samples we found downstaging in 46% of the T and 34.5% of the N stage. We have no information on increased postoperative complications. We followed 86 patients after neoadjuvant therapy. Until March 2009 there was no progression in 48 of our patients. In 13 cases local relapse occurred, and in 25 cases the disease progressed because of distant metastasis, although local control was maintained. 10 patients had local relapse and distant metastases. 17 patients passed away. As a conclusion, neoadjuvant RCT of Stage II-III patients is an effective and well tolerated treatment, allowing for high R0 resection rate and bearing no higher risk for postoperative morbidity.

Preventing apoptotic cell death by a novel small heat shock protein.

NCBI database analysis indicated that the human C1orf41 protein (small heat shock-like protein-Hsp16.2) has sequence similarity with small heat shock proteins (sHsps). Since sHsps have chaperone function, and so prevent aggregation of denatured proteins, we determined whether Hsp16.2 could prevent the heat-induced aggregation of denatured proteins. Under our experimental conditions, recombinant Hsp16.2 prevented aggregation of aldolase and glyceraldehyde-3-phosphate dehydrogenase, and protected Escherichia coli cells from heat stress indicating its chaperone function. Hsp16.2 also formed oligomeric complexes in aqueous solution. Hsp16.2 was found to be expressed at different levels in cell lines and tissues, and was mainly localized to the nucleus and the cytosol, but to a smaller extent, it could be also found in mitochondria. Hsp16.2 could be modified covalently by poly(ADP ribosylation) and acetylation. Hsp16.2 over-expression prevented etoposide-induced cell death as well as the release of mitochondrial cytochrome c and caspase activation. These data suggest that Hsp16.2 can prevent the destabilization of mitochondrial membrane systems and could represent a suitable target for modulating cell death pathways.

X-linked hyper-IgM syndrome associated with a rapid course of multifocal leukoencephalopathy.

OBJECTIVE: To report an exceptional association between X-linked hyper-IgM syndrome and progressive multifocal leukoencephalopathy. DESIGN: Clinical, immunological, and histological analysis. Patient A 19-year-old male patient with X-linked hyper-IgM syndrome developed typical signs and symptoms of progressive multifocal leukoencephalopathy. RESULTS: The serum level of IgA was decreased; the serum level of IgM was slightly increased; and the serum level of IgG was normal as a result of monthly infusions of immunoglobulin. The expression of CD40 ligand on T cells was markedly reduced in the patient. Magnetic resonance imaging indicated confluent lesions involving the majority of the right hemisphere with a mass effect. The patient died after 6 weeks despite combined antiviral treatment. CONCLUSION: Progressive multifocal leukoencephalopathy may follow a rapid course in patients with X-linked hyper-IgM syndrome because of global defects of cellular and B cell responses.

Unaltered development of the archi- and neocortex in prematurely born infants: genetic control dominates in proliferation, differentiation and maturation of cortical neurons.

The development of cerebral cortex includes highly organized, elaborate and long-lasting series of events, which do not come to an end by the time of birth. Indeed, many developmental events continue after the 40th postconceptual week resulting in a long morphological, behavioral and cognitive development of children. Premature birth causes an untimely dramatic change in the environment of the human fetus and often results in serious threats for life. Cognitive abilities of prematurely born children vary, but a correlation between cognitive impairment and the time of birth is evident. In this study we review the morphological evidence of cortical maturation in preterm and full-term infants. Various aspects of postnatal cortical development including cell proliferation and maturation of neurons in the temporal archi- and neocortex are discussed and compared in preterm infants and age-matched full-term controls. Our results suggest that cell proliferation and maturation are not influenced by the preterm delivery. In contrast, the perinatal decrease of the number of Cajal-Retzius cells might be regulated by a mechanism that is affected by preterm birth. We demonstrate that cognitive deficiencies of the prematurely born infants cannot be explained with light microscopically observed alteration of proliferation and maturation of neurons.

Correlation between the progressive cytoplasmic expression of a novel small heat shock protein (Hsp16.2) and malignancy in brain tumors.

BACKGROUND: Small heat shock proteins are molecular chaperones that protect proteins against stress-induced aggregation. They have also been found to have anti-apoptotic activity and to play a part in the development of tumors. Recently, we identified a new small heat shock protein, Hsp16.2 which displayed increased expression in neuroectodermal tumors. Our aim was to investigate the expression of Hsp16.2 in different types of brain tumors and to correlate its expression with the histological grade of the tumor. METHODS: Immunohistochemistry with a polyclonal antibody to Hsp16.2 was carried out on formalin-fixed, paraffin-wax-embedded sections using the streptavidin-biotin method. 91 samples were examined and their histological grade was defined. According to the intensity of Hsp16.2 immunoreactivity, low (+), moderate (++), high (+++) or none (-) scores were given. Immunoblotting was carried out on 30 samples of brain tumors using SDS-polyacrylamide gel electrophoresis and Western-blotting. RESULTS: Low grade (grades 1-2) brain tumors displayed low cytoplasmic Hsp16.2 immunoreactivity, grade 3 tumors showed moderate cytoplasmic staining, while high grade (grade 4) tumors exhibited intensive cytoplasmic Hsp16.2 staining. Immunoblotting supported the above mentioned results. Normal brain tissue acted as a negative control for the experiment, since the cytoplasm did not stain for Hsp16.2. There was a positive correlation between the level of Hsp16.2 expression and the level of anaplasia in different malignant tissue samples. CONCLUSION: Hsp16.2 expression was directly correlated with the histological grade of brain tumors, therefore Hsp16.2 may have relevance as becoming a possible tumor marker.

Epigenetic inactivation of the hMLH1 gene in progression of gliomas.

Gliomas (GLs) are characterized by highly variable biologic behavior. After surgical resection and postoperative therapy, they frequently recur with the same or higher-grade histology. Although a number of genetic aberrations have been described in different histologic types of GLs, the molecular mechanisms of histologic and clinical progression are poorly understood. In this study, we have performed longitudinal mismatch repair gene polymerase chain reaction-single strand conformation polymorphism and methylation analysis in paired samples of primary and recurrent GLs to reveal whether the inactivation of the normal DNA repair mechanism is associated with tumor progression. Polymerase chain reaction-single strand conformation polymorphism analysis of the hMLH1 gene was performed in 24 cases, in each case the samples of the first and second biopsies being evaluated simultaneously, but no alterations in the hMLH1 gene were found. Methylation analysis of the CpG sites in the hMLH1 promoter revealed a total of 4 (16.6%) hypermethylations in recurrent GLs. These results suggest that hMLH1 promoter hypermethylation may occur in low-grade GLs, associated with the development and progression of moderate malignant GL, but not with structural alterations in the hMLH1 gene. It seems that hMLH1 promoter hypermethylation is an early event in the development and progression or the clonal evolution of GLs, this gene inactivation proving stable even on tumor recurrence.

[Progressive multifocal leukoencephalopathy]. / Progresszív multifokális leukoencephalopathia.

Progressive multifocal leukoencephalopathy is a rare disease caused by the reactivation of an opportunistic agent, JC virus almost in every cases in immunodeficient conditions. The disease is characterized by multifocal demyelinating lesions of the central nervous system and causes death within a few months. The authors report two patients: a 67 year-old male treated because of chronic lymphoid leukemia, and a 19 year-old male having a hereditary immunodeficiency, X-linked hyper IgM syndrome. In both cases continuously progressive right, later both hemispheric signs were detected. Cerebrospinal fluid was not helpful. Brain MRI showed bilateral large, white matter lesion. The progression was not influenced by the treatment, finally both patient died ten and six weeks after the appearance of first complaints. The diagnosis was confirmed by brain biopsy and autopsy in both cases. Our cases demonstrate that progressive multifocal leukoencephalopathy can develop in various immunodeficiencies.

Fetal development of membrane water channel proteins aquaporin-1 and aquaporin-4 in the human brain.

Aquaporin-1 and aquaporin-4, water channel membrane proteins reported in both experimental animals and in adult humans, have been detected in different, non-overlapping areas of the central nervous system. This immunohistochemical study describes the developmental expression pattern of the water channel membrane proteins, aquaporin-1 and aquaporin-4, in various structures of human fetal brain over the gestational period of 14-40 weeks. Aquaporin-1 immunostaining was exclusively found in the epithelial cells of the choroid plexus from the 14th gestational week, and the staining pattern altered slightly over time. At week 14, immunostaining appeared only in the apical cell membranes. By the 18th gestational week, the entire plasma membrane of these apical cells was immunopositive, as well as was the cytosol. These changes in immunoreactivity indicate an increasing production of aquaporin-1 in the epithelial cells during the period between the 14th and 24th weeks of gestation. Aquaporin-4 immunostaining was first detected in the archicortex, from gestational week 14 and was detected in the neocortex, 6-7 weeks later. Immunostained structures were always astrocytes, particularly the astrocytic endfeet in the ventricular wall, at the developing ependymal lining, at the pial surface, and around the capillaries. Neuronal labeling was not observed. These results in human fetal brain lend morphological support to the previous findings that aquaporin-1 and aquaporin-4 play different roles in the regulation of the water homeostasis of the brain.

A novel frame shift mutation in the HMG box of the SRY gene in a patient with complete 46,XY pure gonadal dysgenesis.

Pure gonadal dysgenesis or Swyer syndrome is a sex-reversal disorder resulting from embryonic testicular regression sequences especially during the first few weeks of fetal life and is induced by mutations in the SRY gene. In the present report, we describe a nonmosaic XY sex-reversed female with pure gonadal dysgenesis. Molecular analysis using sequential PCR to detect Y chromosomal microdeletions showed the presence of SRY, ZFY and AZFa, b and c regions. Automated sequencing of the SRY region revealed a new mutation (deletion of A (adenine) in codon 82 at position +244), leading to a frame shift mutation within the helix I of the HMG-box domain. This mutation generates a truncated protein and is very likely to produce an impairment of SRY DNA binding activity. The present findings further support the functional importance of the putative DNA binding activity of the SRY HMG-box domain.

[Regulation of water transport in brain oedema]. / Az agyi víztranszport szabályozása agyoedemában.

The study gives an overview on the regulation of cerebral water content and of brain volume. The molecular mechanisms of the development and resolution of various oedema forms are discussed in detail. The physiological and pathophysiological role of the recently discovered molecular water channel proteins aquaporin-1 (AQP1) and aquaporin-4 (AQP4) as well as the importance of central neuroendocrine regulation by vasopressin and atriopeptin are reviewed based on the relevant literature and personal studies. Quantitative water maps based on the combination of multicompartment-T2, diffusion weighted MRI and T1 studies have proven to be powerful tools for studying new drugs against brain oedema brought about by various neuropathological conditions and for testing their efficacy both in animal experimental and clinical conditions. Non-peptide vasopressin antagonists, atriopeptin agonists and drugs targeting AQP4 are potential new families of oedema-decreasing drugs.

Microsatellite analysis of primary and recurrent glial tumors suggests different modalities of clonal evolution of tumor cells.

Gliomas are characterized by highly variable biological behavior. After surgical resection and postoperative therapy they frequently recur with the same or higher-grade histology. Although a number of genetic aberrations have been described in gliomas of different histological types, the molecular mechanisms of the histological and clinical progression are poorly understood. In this study, we performed longitudinal microsatellite and mismatch repair gene analysis in paired samples of primary and recurrent gliomas in order to reveal whether genetic instability is associated with tumor progression. The 7 microsatellite loci of the 7 patients displayed a total of 18 (54.5%) alterations in the primary and 15 (45.5%) alterations in the recurrent gliomas as compared with the corresponding non-neoplastic cells, but no alterations were found in the hMLH1 and hMSH2 genes. These results suggest that microsatellite instability is associated with the development of the primary gliomas rather than with the recurrence or progression, and it is not associated with structural alterations in the hMLH1 or hMSH2 genes. Comparison of the microsatellite patterns in primary and secondary gliomas revealed 4 different modalities of clonal evolution, involving clonal identity, clonal deletion, clonal progression, and different clonality, suggesting that intensive clonal selection may play a central part in the recurrence of gliomas.

Rare sellar region tumors.

We present three cases of rare intracranial midline tumor in the sellar region, often mimicking pituitary adenomas clinically. We describe their symptoms, radiological and pathomorphological features. The first case is a pituitary adenoma producing growth hormone with ganglion cell differentiation. In addition, a rare intracranial granular cell tumor of sellar region and germinoma of pituitary fossa are also presented. All tumors were resected and histologically analyzed. Their biological behaviour was favorable with a 10-year follow-up demonstrating no recurrent tumor mass.

[Current aspects in neurocysticercosis]. / A neurocysticercosis aktualitása napjainkban.

Neurocysticercoses with intraventricular cysts are presented in two operated patients. Cysticercosis, the most frequent parasitic infection of the central nervous system develops only sporadically in Hungary. In this paper epidemiology, different presenting forms, diagnosis, differential diagnosis and therapy are summarized. The purpose of the authors with this publication is to call attention to the diagnosis and the adequate treatment of neurocysticercosis imported from endemic areas.

Concurrent hypermethylation of DNMT1, MGMT and EGFR genes in progression of gliomas.

BACKGROUND: Gliomas are the most common neoplasm of the brain. High-grade gliomas often resist treatment even with aggressive surgical resection and adjuvant radiation and chemotherapy. Despite the combined treatment, they frequently recur with the same or higher-grade histology. Genetic instability is commonly associated with inactivation of the normal DNA repair function and tumour suppressor genes as well as activation of oncogenes resulting from alterations of promoter hypermethylation, but the molecular mechanisms of the histological and clinical progression of gliomas are still poorly understood. METHODS: This study involved longitudinal analysis samples of primary and recurrent gliomas to determine whether the progression of low- and high-grade gliomas is associated with the promoter methylation of the DNMT1, MGMT and EGFR genes by PCR-based restriction enzyme assay. Epigenetic inactivation of these three important glioma-associated genes was analyzed in paired biopsy samples from 18 patients with tumour recurrence. RESULTS: The methylation analysis of the CpG sites in the DNA methyltransferase (DNMT1) promoter revealed a total of 6 hypermethylations (6/18), the methylguanine-DNA methyltransferase (MGMT) promoter revealed a total of 10 hypermethylations (10/18) and the epithelial grow factor receptor (EGFR) promoter revealed a total of 12 (12/18) hypermethylations respectively in recurrent gliomas. The results demonstrated that DNMT1 promoter hypermethylation does not occur in low-grade gliomas, it was mainly observed in secondary glioblastomas. Additionally, the MGMT and EGFR promoter was hypermethylated in both low-and high-grade GLs and their corresponding histological transformed GLs. CONCLUSION: This study has provided further evidence that the histological transformation and progression of gliomas may be associated with the inactivation of the EGFR and MGMT genes. It seems that EGFR and MGMT promoter hypermethylations are early events in the clonal evolution of gliomas and this gene inactivation has proved to be stable even in tumour recurrence. However, the DNMT hypermethylation is a late part of glioma progression. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1935054011612460.