Prevalence and prognosis of PIK3CA mutations in Bulgarian patients with metastatic breast cancer receiving endocrine therapy in first-line setting

BACKGROUND AND AIMS

In approximately 40% of patients with HER2-negative/HR-positive breast cancer tumors, the PIK3CA gene is mutated. Despite this, clinical outcomes vary between studies in this cohort. We aimed to ascertain the prevalence of PIK3CA mutations in patients with metastatic HR+/HER2- breast in Bulgaria, as well the evaluation and comparison of progression free survival (PFS) between wild-type (WT) and mutation-positive groups in the real-world setting.

METHODS

Three oncology centers in Bulgaria collected 250 tissue samples between 2016 and 2022 for this multicentric retrospective study. PIK3CA mutations were identified using Real-Time qPCR. The median follow-up period was 35 months.

RESULTS

The mean age of the mutant cohort was 57.6 ± 11.6 years, compared to 56.5 ± 12.2 years for the WT cohort (p = .52). The percentage of patients with visceral metastasis was 58.8% (n = 147). Approximately 84.3% (n = 210) of the patients had reached postmenopause. 29.2% (n = 73) of the patients had PIK3CA mutations. The predominant mutation was present in exon 20, H1047R (46.5%). We found a significant correlation only between the presence of a mutation and the metastatic diseases at diagnosis (p = .002). As first-line therapy, 67.1% of patients received endocrine therapy (ET) plus cyclin dependent kinase (CDK4/6) inhibitor, while the remainder received ET alone. The median PFS of patients in the group with the mutation was 32 months (95%, CI: 22-40) compared to 24 months in the WT cohort ((95%, CI: 21-36) (p = .45)); HR = 0.86 (95%, CI: 0.5-1.3) (p = .46). We corroborated our conclusion using propensity matching score analysis, (36 months [95% CI: 20-40] vs. 26 months [95% CI: 21-38], [p = .69]).

CONCLUSIONS

We found that the prevalence of PIK3CA mutations in our patients was comparable to what has been reported in other nations. Our results suggest that PIK3CA mutational status has no bearing to ET efficacy in first-line setting.

Clinical impact of copy number variation changes in bladder cancer samples

The aim of the present study was to detect copy number variations (CNVs) related to tumour progression and metastasis of urothelial carcinoma through whole-genome scanning. A total of 30 bladder cancer samples staged from pTa to pT4 were included in the study. DNA was extracted from freshly frozen tissue via standard phenol-chloroform extraction and CNV analysis was performed on two alternative platforms (CytoChip Oligo aCGH, 4x44K and Infinium OncoArray-500K BeadChip; Illumina, Inc.). Data were analysed with BlueFuse Multi software and Karyostudio, respectively. The results highlight the role of genomic imbalances in regions containing genes with metastatic and proliferative potential for tumour invasion. A high level of genomic instability in uroepithelial tumours was observed and a total of 524 aberrations, including 175 losses and 349 gains, were identified. The most prevalent genetic imbalances affected the following regions: 1p, 1q, 2q, 4p, 4q, 5p, 5q, 6p, 6q, 7q, 8q, 9p, 9q, 10p, 10q, 11q, 13q and 17q. High-grade tumours more frequently harboured genomic imbalances (n=227) than low-grade tumours (n=103). A total of 36 CNVs in high-grade bladder tumours were detected in chromosomes 1-5, 8-11, 14, 17, 19 and 20. Furthermore, five loss of heterozygosity variants containing 176 genes were observed in high-grade bladder cancer and may be used as potential targets for precision therapy. Revealing specific chromosomal regions related to the metastatic potential of uroepithelial tumours may lay a foundation for implementing molecular CNV profiling of bladder tumours as part of a routine progression risk estimation strategy, thus expanding the personalized therapeutic approach.

Centenarian Exomes as a Tool for Evaluating the Clinical Relevance of Germline Tumor Suppressor Mutations

Objectives:

The aim of the present study was to evaluate the clinical relevance of mutations in tumor suppressor genes using whole-exome sequencing data from centenarians and young healthy individuals.

Methods:

Two pools, one of centenarians and one of young individuals, were constructed and whole-exome sequencing was performed. We examined the whole-exome sequencing data of Bulgarian individuals for carriership of tumor suppressor gene variants.

Results:

Of all variants annotated in both pools, 5080 (0.06%) are variants in tumor suppressor genes but only 46 show significant difference in allele frequencies between the two studied groups. Four variants (0.004%) are pathogenic/risk factors according to single nucleotide polymorphism database: rs1566734 in PTPRJ, rs861539 in XRCC3, rs203462 in AKAP10, and rs486907 in RNASEL.

Discussion:

Based on their high minor allele frequencies and presence in the centenarian group, we could reclassify them from pathogenic/risk factors to benign. Our study shows that centenarian exomes can be used for re-evaluating the clinically uncertain variants.

Unbalanced human embryos secrete more hyperglycosylated human chorionic gonadotrophin (hCG-H) than balanced ones

PURPOSE

The aim of this study was to compare the levels of hyperglycosylated human chorionic gonadotropin (hCG-H) secreted from balanced and unbalanced human embryos.

METHODS

Single-step culture media samples from 155 good quality embryos, derived from 90 good prognosis patients undergoing intracytoplasmic sperm injection (ICSI), were collected on the fifth day of embryo cultivation. All embryos were tested by next-generation sequencing (NGS) technique. The hCG-H levels in the culture media were evaluated by ELISA kit (Cusabio Biotech, CBS-E15803h) according to the manufacturer's instructions. Statistical analysis was performed using SPSS v.21 (IBM Corp., Armonk, NY, USA).

RESULTS

The NGS analysis revealed that 36% of the embryos (n = 56) were balanced, and 64% of the embryos were unbalanced (n = 99). The presence of hCG-H was confirmed in all embryo culture media samples but was absent in the negative control. In addition, hCG-H concentration was significantly higher in the culture media from unbalanced embryos compared with the balanced ones (0.72 ± 0.30 mIU/ml vs. 0.62 ± 0.12 mIU/ml, p = 0.02, respectively). Furthermore, the mean levels of hCG-H were significantly increased in the samples from embryos with multiple abnormalities. Finally, the highest levels of hCG-H were expressed from embryos with monosomy of chromosome 11 (1.28 ± 0.04 mIU/ml) and those with trisomies of chromosomes 21 (2.23 mIU/ml) and 4 (1.02 ± 0.35 mIU/ml).

CONCLUSION

Our results suggest that chromosomal aberrations in human embryos are associated with an increased secretion of hCG-H. However, hCG-H concentration in embryo culture media as a single biomarker is not sufficient for an accurate selection of balanced embryos.

Ancient human mitochondrial genomes from Bronze Age Bulgaria: new insights into the genetic history of Thracians

One of the best documented Indo-European civilizations that inhabited Bulgaria is the Thracians, who lasted for more than five millennia and whose origin and relationships with other past and present-day populations are debated among researchers. Here we report 25 new complete mitochondrial genomes of ancient individuals coming from three necropolises located in different regions of Bulgaria – Shekerdja mogila, Gabrova mogila and Bereketska mogila – dated to II-III millennium BC. The identified mtDNA haplogroup composition reflects the mitochondrial variability of Western Eurasia. In particular, within the ancient Eurasian genetic landscape, Thracians locate in an intermediate position between Early Neolithic farmers and Late Neolithic-Bronze Age steppe pastoralists, supporting the scenario that the Balkan region has been a link between Eastern Europe and the Mediterranean since the prehistoric time. Spatial Principal Component Analysis (sPCA) performed on Thracian and modern mtDNA sequences, confirms the pattern highlighted on ancient populations, overall indicating that the maternal gene pool of Thracians reflects their central geographical position at the gateway of Europe.

Metachronous Development of Meningothelial Meningioma, Basal Cell Carcinoma, and Glioblastoma Multiforme in a Patient with Pancreatic Incidentaloma

We report the unique case of a 61-year-old male patient with known pancreatic incidentaloma who additionally developed 3 other histologically different tumors: left sphenoid wing meningothelial meningioma, basal cell carcinoma of the occiput, and right occipital lobe glioblastoma multiforme. The latter were totally removed with a favorable clinical outcome. The patient's family history was unremarkable, and no data on any previous head and neck irradiation were found.

Evaluation of Hepcidin and Atherosclerosis in Dialysis Patients

BACKGROUND

Chronic kidney disease (CKD) is a condition that involves 10% - 15% of population worldwide, which increases the risk of cardio-vascular diseases (CVD). Chronic kidney disease is one of the main reasons for illness and mortality in the world. Chronic kidney disease is a serious health problem caused by involvement of a large number of patients with kidney injury, especially in industrial countries. Among the main reasons for this are population living longer and the number of diseases in elderly persons, such as diabetes mellitus type 2, hypertension, and cardio-vascular diseases.

METHODS

We evaluated 63 patients on chronic dialysis at the Dialysis Centre at University "Aleksandrovska" Hospital; the average age was 49.9 ± 7.8. Their results were compared to 63 age matched controls. Blood samplings were taken before dialysis procedure. In the included groups, we measured CBC, serum iron (by Ferrozine method), ferritin, soluble transferrin receptors and hsCRP (by nephelometric method), hepcidin (by ELISA method), and homocysteine (by CLIA method). IMT was measured by using electronic calipers and evaluated by automated software programs.

RESULTS

We established elevated serum hepcidin levels in CKD patients (205.1 ± 29.9 µg/L) compared to the control group (20.8 ± 3.1 µg/L), p < 0.001. Serum homocysteine and hsCRP concentrations were elevated in CKD cases (48.7 ± 6.8 µmol/L; 29.7 ± 4.1 mg/L) compared to controls (7.9 ± 1.8 µmol/L; 1.1 ± 0.4 mg/L), p < 0.005. In patients with CKD we found a strong positive correlation between serum hepcidin and homocysteine concentrations, r = 0.879, p < 0.001. In patients with impaired kidney function soluble transferrin receptors correlated negatively to hepcidin: r = -0.799, p < 0.001. In dialysis, the transferrin concentration correlated highly positive to hepcidin: r = 0.691, p < 0.001. IMT in CKD patients correlated positively to hepcidin and homocysteine levels: r = 0.788 and r = 0.841, respectively, p < 0.005.

CONCLUSIONS

Chronic kidney disease is connected to cardio-vascular disease risk factors. CKD might be an independent CVD risk factor. In early kidney injury stages, increased morbidity is found from CVD. The risk of fatal and non-fatal cardio-vascular incidents is connected to kidney injury. For clinical practice, early evaluation of hepcidin and atherosclerosis in chronic kidney disease patients is very important.

Benign, Pathogenic and Copy Number Variations of Unknown Clinical Significance in Patients with Congenital Malformations and Developmental Delay

The high frequency (3.0-5.0%) of congenital anomalies (CA) and intellectual disabilities (IDs), make them a serious problem, responsible for a high percentage (33.0%) of neonatal mortality. The genetic cause remains unclear in 40.0% of cases. Recently, molecular karyotyping has become the most powerful method for detection of pathogenic imbalances in patients with multiple CAs and IDs. This method is with high resolution and gives us the opportunity to investigate and identify candidate genes that could explain the genotype-phenotype correlations. This article describes the results from analysis of 81 patients with congenital malformations (CMs), developmental delay (DD) and ID, in which we utilized the CytoChip ISCA oligo microarray, 4 × 44 k, covering the whole genome with a resolution of 70 kb. In the selected group of patients with CAs, 280 copy number variations (CNVs) have been proven, 41 were pathogenic, 118 benign and 121 of unknown clinical significance (average number of variations 3.5). In six patients with established pathogenic variations, our data revealed eight pathogenic aberrations associated with the corresponding phenotype. The interpretation of the other CNVs was made on the basis of their frequency in the investigated group, the size of the variation, content of genes in the region and the type of the CNVs (deletion or duplication).

Genetic, Genomic and Epigenomic Studies of Balkan Endemic Nephropathy (Ben)

BEN is a primary, chronic tubulointerstitial nephritis characterized with chronic anemia, absence of edema, xantoderma, normal blood pressure and normal findings on the fundus oculi. The disease is distributed in restricted areas in Bulgaria, Romania, Croatia, Bosnia, Former Yugoslavia. Despite numerous studies on genetic and environmental factors and their possible involvement in BEN, its etiopathogenesis still remains elusive. Our recent study aim to elucidate the possible epigenetic component in BEN development. Whole genome DNA array methylation analysis was applied to compare the methylation profiles of male and female BEN patients from endemic regions in Bulgaria and Serbia and healthy controls. All three most prominent candidate genes with aberrations in the epigenetic profile discovered with this study are involved in the inflammatory/immune processes and oncogenesis. These data are in concordance with the reported pathological alterations in BEN. This research supports the role of epigenetic changes in BEN pathology. Exome sequencing of 22.000 genes with Illumina Nextera Exome Enrichment Kit revealed three mutant genes (CELA1, HSPG2, and KCNK5) in BEN patients which encode proteins involved in basement membrane/extracellular matrix and vascular tone, tightly connected to process of angiogenesis. We suggest that an abnormal process of angiogenesis plays a key role in the molecular pathogenesis of BEN.

Gene expression in peripheral blood of patients with hypertension and patients with type 2 diabetes

AIM

To evaluate the expression of atherosclerosis-associated genes in patients with hypertension and type 2 diabetes mellitus.

MATERIAL AND METHODS

Twenty-seven patients (14 men, 13 women), mean age 43.26 ± 11.69 years, were included in the study, which was divided into three groups: group 1 - patients with newly diagnosed hypertension and normal glucose tolerance (n = 9), group 2 - normotensive individuals with newly diagnosed type 2 diabetes (n = 9), and control group - normotensive individuals with normal glucose tolerance (n = 9). Gene expression analysis was performed with Human Atherosclerosis RT2 Profiler PCR Array.

RESULTS

In patients with hypertension, we found eight genes with increased expression - FABP3, FAS, FN1, IL1R2, LPL, SERPINE1, TGFB1, and VCAM1. Decreased expression was observed for two genes - SELPLG and SERPINEB2. In patients with type 2 diabetes we found seven up-regulated genes - APOE, BAX, MMP1, NFKB1, PDGFB, SPP1, and TGFB2, whereas no specifically down-regulated genes were observed. Three genes - KLF2, PDGFRB, and PPARD were found to be expressed only in groups 1 and 2.

CONCLUSION

Hypertension is associated with increased expression of FABP3, FAS, FN1, IL1R2, LPL, SERPINE1, TGFB1, and VCAM1 and decreased expression of SELPLG and SERPINEB2. The up-regulation of FAS, FN1, SERPINE1, TGFB1, and VCAM1 might be associated with an increased cardiovascular risk. Type 2 diabetes is associated with increased expression of APOE, BAX, MMP1, NFKB1, PDGFB, SPP1, and TGFB2. KLF2 and PPARD might be part of protective mechanisms that limit target organ damage in both disease conditions. Expression of PDGFRB might play an important role in the pathogenesis of both hypertension and type 2 diabetes.

Whole genome methylation analyses of schizophrenia patients before and after treatment

The aetiology of schizophrenia is still unknown but it involves both heritable and non-heritable factors. DNA methylation is an inheritable epigenetic modification that stably alters gene expression. It takes part in the regulation of neurodevelopment and may be a contributing factor to the pathogenesis of brain diseases. It was found that many of the antipsychotic drugs may lead to epigenetic modifications. We have performed 42 high-resolution genome-wide methylation array analyses to determine the methylation status of 27,627 CpG islands. Differentially methylated regions were studied with samples from 20 Bulgarian individuals divided in four groups according to their gender (12 males/8 females) and their treatment response (6 in complete/14 in incomplete remission). They were compared to two age and sex matched control pools (110 females in female pool/110 males in male pool) before and after treatment. We found significant differences in the methylation profiles between male schizophrenia patients with complete remission and control male pool before treatment (C16orf70, CST3, DDRGK1, FA2H, FLJ30058, MFSD2B, RFX4, UBE2J1, ZNF311) and male schizophrenia patients with complete remission and control male pool after treatment (AP1S3, C16orf59, KCNK15, LOC146336, MGC16384, XRN2) that potentially could be used as target genes for new therapeutic strategies as well as markers for good treatment response. Our data revealed major differences in methylation profiles between male schizophrenia patients in complete remission before and after treatment and healthy controls which supports the hypothesis that antipsychotic drugs may play a role in epigenetic modifications.

Next-generation sequencing of BRCA1 and BRCA2 in breast cancer patients and control subjects

Breast cancer is currently the most common type of cancer in females. The majority of the hereditary forms of breast cancer are caused by mutations in the BRCA1 and BRCA2 genes, whose main function is the DNA repair of double-strand breaks. Genetic testing of females with a family history of breast cancer is recommended to determine their hereditary predisposition for this type of cancer. The variants with no clear clinical significance may represent a diagnostic challenge when performing targeted resequencing. In this study, DNA samples were obtained from 24 breast cancer patients (mean age, 35±10 years) with a positive family history and from 71 age-matched healthy controls. Informed consent was obtained from all the subjects. Sequence-targeted BRCA1 and BRCA2 libraries were prepared using the TruSeq Custom Amplicon method and sequenced on the Illumina MiSeq system. A wide range of variants were identified in the BRCA1 and BRCA2 genes. Two pathological/presumably pathological variants were detected in the breast cancer patient group: a mutation in BRCA2 at the chromosomal (chr) position chr13:32890665, which affected the first position of the 5' splice region following exon 2; and a mutation in BRCA1 at chr17:41219635, causing an in-frame triple nucleotide deletion of valine 1688 (8.3%). In the patient and control groups, 7 likely polymorphic variants and 13 common variants were detected in the BRCA1 and BRCA2 genes. To the best of our knowledge, this study was the first to identify 3 common polymorphisms in BRCA2, characteristic solely of the Bulgarian population, including chr13:32973737, T/-, a single-nucleotide polymorphism (SNP) within the 3'-UTR of exon 27; chr13:32973280, A/-, a mononucleotide deletion within the 5'-UTR of exon 27; and chr13:32973924, T/-, a mononucleotide deletion downstream of the gene sequence. To the best of our knowledge, this study was the first to apply next-generation sequencing of the BRCA1 and BRCA2 genes in a Bulgarian population, prompting further investigation for local founder mutations and variants characteristic for this particular region.

Whole genome methylation array analysis reveals new aspects in Balkan endemic nephropathy etiology

Background

Balkan endemic nephropathy (BEN) represents a chronic progressive interstitial nephritis in striking correlation with uroepithelial tumours of the upper urinary tract. The disease has endemic distribution in the Danube river regions in several Balkan countries.

DNA methylation is a primary epigenetic modification that is involved in major processes such as cancer, genomic imprinting, gene silencing, etc. The significance of CpG island methylation status in normal development, cell differentiation and gene expression is widely recognized, although still stays poorly understood.

Methods

We performed whole genome DNA methylation array analysis on DNA pool samples from peripheral blood from 159 affected individuals and 170 healthy individuals. This technique allowed us to determine the methylation status of 27 627 CpG islands throughout the whole genome in healthy controls and BEN patients. Thus we obtained the methylation profile of BEN patients from Bulgarian and Serbian endemic regions.

Results

Using specifically developed software we compared the methylation profiles of BEN patients and corresponding controls and revealed the differently methylated regions. We then compared the DMRs between all patient-control pairs to determine common changes in the epigenetic profiles.

SEC61G, IL17RA, HDAC11 proved to be differently methylated throughout all patient-control pairs. The CpG islands of all 3 genes were hypomethylated compared to controls. This suggests that dysregulation of these genes involved in immunological response could be a common mechanism in BEN pathogenesis in both endemic regions and in both genders.

Conclusion

Our data propose a new hypothesis that immunologic dysregulation has a place in BEN etiopathogenesis.

Chromosomal radiosensitivity in patients with multiple sclerosis

Multiple sclerosis is a clinically heterogeneous autoimmune disease leading to severe neurological disability. Although during the last years many disease-modifying agents as treatment options for multiple sclerosis have been made available, their mechanisms of action are still not fully determined. In the present study radiosensitivity in lymphocytes of patients with relapsing-remitting multiple sclerosis, secondary progressive multiple sclerosis and healthy controls was investigated. Whole blood cultures from multiple sclerosis patients and healthy controls were used to analyze the spontaneous and radiation-induced micronuclei in binucleated lymphocytes. A subgroup of patients with relapsing-remitting multiple sclerosis was treated with immunomodulatory agents, interferon β or glatiramer acetate. The secondary progressive multiple sclerosis patients group was not receiving any treatment. Our results reveal that the basal DNA damage was not different between relapsing-remitting and secondary progressive multiple sclerosis patients, and healthy controls. No differences between gamma-irradiation induced micronuclei frequencies in binucleated cells from relapsing-remitting and secondary progressive multiple sclerosis patients, and healthy controls were found either. Nevertheless, when we compared the radiation induced DNA damage in binucleated cells from healthy individuals with the whole group of patients, a reduction in the frequency of micronuclei was obtained in the patients group. Induced micronuclei yield was significantly lower in the irradiated samples from treated relapsing-remitting multiple sclerosis patients than in healthy controls and relapsing-remitting not treated patients. Intrinsic sensitivity of lymphocytes subpopulations to the apoptotic effect of immunomodulatory treatment could be responsible for this result.

[Genomic study in patients with idiopathic azoospermia and oligoasthenoteratozoospermia]

Genome disbalances are related to the different types of infertility and they play a role in the treatment of human infertility. Comparative genome hybridization (CGH) combined with microchips is a modern high resolution technique for all human chromosomes investigations. We analysed the genome disbalances in 16 blood samples of men with an idiopathic oligoastenozoospermia or azoospermia using CGH and microchips for the whole human genome. Our data showed a few affected loci, including: 3q26.32 deletion accompanied by 14q11.1 deletion, 9q12 deletion, 5q35.1 amplification, 7p22.3 amplification and 17q12-17q21.2 amplification. In this study we have match the deletions: in two patients in the same area in the 8 chromosome, as well as in 5 patients in 14 chromosome. The deleted region contains 25 genes. Two of them (SPAG11B and SPAG11A) are associated with stages of spermatogenesis and in particular formation and maturation of the spermatozoa. These genes play a role during spermatogenesis and fertilization. Loss. chr.14q11.2 (EDDM3A and EDDM3B) affected the proteins that are synthesized and secreted by epididymal epithelial cells that has been found up-regulated in epididimis of nonobstructive azoospermic men. Our results displayed the significance of CGH and microchip analysis as a promising area of research with serious clinical application for resolving the problems of the male infertility and still have an important annex for selecting the most appropriate methods for the treatment in these patients as a perspective scientific field of investigations with a clinical appliance.

Genome-wide association study on bipolar disorder in the Bulgarian population

Bipolar disorder is a severe psychiatric disorder influenced by environmental and genetic factors. Genetic studies have implicated many variants in the disease's etiology but only few have been successfully replicated. We conducted a genome-wide association study (GWAS) on bipolar disorder in the Bulgarian population followed by a replication study of the top 100 single nucleotide polymorphisms (SNPs) showing the smallest P values. The GWAS was performed on 188 bipolar disorder patients and 376 control subjects genotyped on the Illumina 550 platform. The replication study was conducted on 122 patients and 328 controls. Although our study did not show any association P value that achieved genome-wide significance, and none of the top 100 SNPs reached the Bonferroni-corrected P value in the replication study, the plausible involvement of some variants cannot be entirely discarded. Three polymorphisms, rs8099939 [P = 2.12 × 10(-6), odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.43-2.67] in GRIK5, rs6122972 (P = 3.11 × 10(-6), OR = 2.02, 95% CI = 1.46-2.80) in PARD6B and rs2289700 (P = 9.14 × 10(-6), OR = 2.13, 95% CI = 1.53-2.95) in CTSH remained associated at a similar level after Mantel-Haenszel test for combining the results from the genome-wide and replication studies. A modest association was also detected for SNP rs1012053 (GWAS P = 4.50 × 10(-2)) in DGKH, which has already been reported as the most significant variant in a previous genome-wide scan on bipolar disorder. However, further studies using larger datasets are needed to identify variants with smaller effects that contribute to the risk of bipolar disorder.

Long-Term Survival of a Patient with Giant Cell Glioblastoma: Case Report and Review of the Literature

Glioblastoma multiforme (GBM) is the most common glial tumor of the central nervous system. Overall survival is less than a year in most of the cases in spite of multimodal treatment approaches. A 45-year-old female with histologically confirmed giant cell GBM was treated at our institution. Subtotal excision of the lesion situated in the right precentral area was performed during the initial stay in August 2005. The patient improved after the procedure with no hypertension and additional neurological deficit. Radiotherapy plus concomitant and adjuvant temozolomide was performed. The patient was symptom-free for 35 months after initial surgery. From July 2008 the patient developed partial motor seizures in the left side of the body and progressive hemiparesis. Local tumor progression was demonstrated on the neuroimaging studies. In December 2008, a second operative intervention was performed with subtotal excision of the tumor. Forty-five months after the initial diagnosis the patient is still alive with moderate neurological deficit. Microarray analysis of the tumor found the following numeric chromosomal aberrations: monosomy 8, 10, 13, 22, and trisomy 21, as well as amplifications in 4q34.1, 4q28.2, 6q16.3, 7q36.1, 7p21.3, and deletions in 1q42.12, 1q32.2, 1q25.2, 1p33, 2q37.2, 18q22.3, 19p13.2, Xq28, and Xq27.3. GBMs seem to be a heterogeneous group of glial tumors with different clinical course and therapeutic response. Microarray analysis is a useful method to establish a number of possible molecular predictors.

[Clinical, histopathological and cytogenetical findings in six cases with primary glioblastoma multiforme]

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor. There is an increasing amount of data demonstrating that the routine histological examination has limited value to predict the tumor biological behaviour.

AIM

To compare the clinical, histological and cytogenetical findings in a group of six patients with primary GBM surgically treated in the Department of Neurosurgery at University Hospital "St. Ivan Rilski"- Sofia, Bulgaria.

MATERIAL AND METHODS

The studied group consisted of three women and three men with average age of 51 years and 6 months. In all patients the diagnosis was histologically confirmed. A microarray comparative genomic hybridization (CGH) analysis of fresh-frozen tumor tissue samples was also made.

RESULTS

In two of the patients the tumor was localized in frontotemporal region, in another two- in frontoparietal, and in the other two- in parietal and occipital respectively. The onset was with headache in three of the cases. The median time between the onset and admission in the clinic was 70 days. Gross-total tumor removal was performed in one patient. In the other five subtotal excision was made. Three of the patients improved after the intervention. One patient deteriorated after the surgery. All patients demonstrated typical histological findings except one who had giant cell subtype of GBM. The microarray CGH analysis determined chromosome 10 monosomy in five patients, trisomy 7 - in four, trisomy 20 - in three, 3q23 deletion - in three, and Yp11.2 deletion - in three.

CONCLUSION

GBMs are genetically heterogeneous tumors with different clinical response to standard multimodal treatment regimens. The microarray CGH analysis is a powerful method which can demonstrate the presence of a number of molecular markers with possible predictive value.