Significance of aberrant DNA methylation for cancer diagnostics and therapy

BACKGROUND

Epigenetics is a scientific field that covers changes in gene expression that are not caused by the alteration of the nucleotide sequence in the DNA strand. Together with sequential changes, epigenetic reprogramming is a recognized cancer hallmark driving carcinogenesis. The underlying mechanisms of epigenetically-driven gene expression changes are diverse. However, one of the most extensively studied mechanisms is a change in DNA methylation. Under physiological conditions, DNA methylation ensures tissue-specific gene silencing and helps to maintain genome stability. With malignant transformation, genomic DNA undergoes global hypomethylation as well as locus-specific hypermethylation in promoters of tumor suppressor genes. In the last few decades, specific aberrant DNA methylation changes have emerged as both cancer-associated biomarkers and therapeutic targets and prompted ongoing efforts to enhance both diagnostic and therapeutic means in oncology.

PURPOSE

The main purpose of this review is to introduce both established and emerging DNA methylation-based biomarkers for cancer diagnostics with a focus on biomarkers that are either routinely used or have been developed as commercial tests with certification for their use within in vitro diagnostics. Furthermore, therapeutic options for targeting aberrant DNA methylation are described, including both approved compounds and newly developed agents undergoing clinical investigation.

Biomarkers as prognostic and predictive factors in patients with hepatocellular carcinoma undergoing radiological oncological interventions

BACKGROUND

Hepatocellular carcinoma is the most common malignant liver tumor in adults and thermal ablation and transarterial embolization are important methods of therapy. Thermal ablation can be used in early stages. Methods based on the transarterial approach, especially transarterial chemoembolization, play an important role in intermediate stage diseases. The success of procedures depends not only on the biological nature and the size of the tumor, on the technical design of the procedure and on the patient's response to treatment, but also on the molecular changes associated with these procedures. In addition to classic predictive and prognostic factors including age, patient comorbidities, Child-Pugh score, tumor characteristics, presence of large surrounding vessels, and portal vein thrombosis, molecular prognostic and predictive factors (serum biomarkers) are often mentioned in studies. Currently, only a-fetoprotein is routinely used as a prognostic biomarker; however, there are studies referring to new serum biomarkers that can potentially help to classical markers and imaging methods to determine the cancer prognosis and predict the success of therapy. These biomarkers most often include g-glutamyltranspeptidase, des- g-carboxyprothrombin, some types of microRNAs, inflammatory and hypoxic substances, whose serum levels are changed by the intervention therapies. Evaluation of these molecules could lead to the optimization of the medical intervention (choice of therapy method, timing of treatment) or change the management of patient follow-up after interventions. Although several biomarkers have shown promising results, most serum biomarkers still require validation in phase III studies.

PURPOSE

The aim of this work is to present a comprehensive overview of classical and molecular biomarkers that could potentially help in the prognostic stratification of patients and better predict the success and effect of radiological intervention methods.

Molecular testing of endometrial carcinoma in real-world clinical practice

BACKGROUND

Molecular classification has brought significant changes in the management of endometrial cancer (EC). In this article, we aim to analyze our first experience with an implementation of molecular testing into daily clinical practice.

MATERIALS AND METHODS

In all newly diagnosed EC, the status of mismatch repair (MMR) and p53 proteins has been evaluated immunohistochemically as a part of the routine histopathological examination since May 2021. In tumors that do not meet clinical criteria for a low risk and those with MMR deficiency or p53 mutation, the molecular genetic testing of the POLE gene is performed as well. Recommendations for adjuvant treatment or follow-up are subsequently made based on the risk of recurrence. Genetic counselling is proposed to all patients with MMR-deficient tumors or family history of cancer.

RESULTS

A total of 85 patients with newly diagnosed EC between May 2021 and May 2022 were enrolled in the analysis. The median age was 66 years. The results of molecular testing were as follows: 22 (26%) MMR-deficient, 8 (9%) p53-mutated and none POLE-ultramutated of those 40 tumors with performed POLE sequencing. A total of 46 (51%) patient had a low risk, 2 (2%) intermediate, 14 (16%) high-intermediate and 20 (24%) patients had a high risk of recurrence. Advanced or metastatic diseases were diagnosed in 6 (7%) patients. The median time between surgery and multidisciplinary tumor board decision was 21 days (8-36). A total of 76 (90%) patients underwent the whole treatment plan according to the recurrence risk. At the time of analysis, the results of genetic testing were available in 18 patients and revealed 4 (22%) carriers of a pathogenic variant in any of the genes associated with Lynch syndrome.

CONCLUSION

Molecular testing combining immunohistochemical analyses of MMR and p53 proteins in all newly diagnosed EC patients with sequencing analysis of POLE in those with non-low-risk disease is feasible and does not prolong the time needed for treatment decision.

Integrated dia-gnostics of diffuse gliomas

Recently, the World Health Organization (WHO) classification of tumours of the central nervous system (CNS) has brought essential changes. The currently valid revised WHO 2016 classification of CNS tumours introduced the concept of integrated dia-gnostics, which incorporated not only histopathological morphological finding and immunophenotype but also molecular-genetic characteristics of the tumour. Thus, the final integrated dia-gnosis comprises the traditional morphological and growth pattern characteristics of a tumour including histopathological grade and also specific molecular bio-markers. The classification of tumour based on a combination of both tumour phenotype and genotype enables more precise prognostic stratification, increases the objectivity of dia-gnostics and prediction of response to treatment. In 2017, an international platform, The Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy - not official WHO (cIMPACT-NOW), was established to create and formulate practical recommendations for integrated dia-gnostics of CNS tumours and upcoming WHO classification. The incorporation of molecular bio-markers into the integrated dia-gnostics radically changed the classification of diffuse gliomas, which include entities with different morphological characteristics, genetic alterations and bio-logical behaviour. This review article summarizes essential morphological, immunophenotypical and molecular genetic characteristics of diffuse gliomas within the scope of integrated dia-gnostics according to the valid WHO classification of tumours of the CNS and subsequent recommendations of dia-gnostic approaches. This work was supported by grant of the Ministry of Health of the Czech Republic - Conceptual Development of a Research Organization (MMCI 00209805) and Grant Agency of Masaryk University (MUNI/A/1562/2018). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.

Swim bladder as a primary site of mycobacterial infection in Nothobranchius 'belly sliders'

The swim bladder inflates early after fish hatching via its interconnection with the digestive tract (ductus pneumaticus). This interconnection may serve as a portal to foreign particles, including bacteria, causing deficiencies in primary swim bladder inflation. We histologically examined 134 African annual killifish (genus Nothobranchius) with secondary loss of swim bladder function ('belly sliders'). We demonstrate that these fish lost the ability of air regulation in their swim bladders likely due to Mycobacterium spp. infection at an individual-specific age. Nearly all examined belly sliders had thickened swim bladder walls, and their swim bladder was filled with material containing mycobacteria, cell debris, young monocytic cells and phagocyting macrophages. Mycobacterial infection was restricted to the swim bladder in juveniles, where mycobacteria likely enter the host through the ductus pneumaticus. Infection in adults was systemic and mycobacteria were present in all examined organs. Presence of mycobacteria in the epithelial lining and submucosal layers of the digestive tract of adults suggests that it may also serve as the entrance site of infection. We suspect 2 sources of Mycobacterium contamination: dietary (with bloodworms) and/or contaminated hatching substrate. These sources of contamination may be eliminated by use of laboratory dry feed and egg disinfection prior to hatching.

Rare Hereditary Burden associated with a Hypercalcemic Small-Cell Carcinoma of Cervix in a Young Female Patient

BACKGROUND

Oncological diseases have, in most cases, a multifactorial etiology, composed of a combination of external and internal environmental factors. Hereditary tumorous syndromes are mostly autosomal dominant diseases with incomplete but very high penetrance.

OBSERVATION

The patient, an 18-year-old virgin female, consulted a gynecologist in June 2018 because of metrorrhagia. Magnetic resonance imaging revealed a cervical tumor with the dimensions 80 × 90 × 80 mm. Histological analysis confirmed the presence of a very rare hypercalcemic type of small-cell carcinoma of the cervix. Further investigation of the germinal exom of the patient showed pathological variations in genes PALB2 and BRCA2, presented with recommendation of detailed examination by medical genetics.

CONCLUSION

Clinical experience with this type of tumor is very limited, but it still comes with some useful outcome. Small cell carcinomas of the gynecologic tract are very rare, aggressive diseases, with very poor prognosis, affecting mainly young women. Their origin is most often the ovaries, based on most clinical data, but these tumor also localize to the endometrium, cervix, vagina and vulva. It is an extremely rare type of cancer, for which clinical data is scant due to the extremely low number of reported cases. In this patient, the carcinoma had an unusual genetical mutation burden, which she inherited from her parents. In the light of these findings, we recommend that patients suspected of having a small-cell of the gynecologic tract provide a detailed family history, and that genetic testing be considered in similar cases. This work was supported by MH CR grant 16-33209A and research program of Charles University Progress Q40/06. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 10. 6. 2019 Accepted: 9. 9. 2019.

Effective Immunotherapy of Glioblastoma in an Adolescent with Constitutional Mismatch Repair-Deficiency Syndrome

BACKGROUND

Individuals with constitutional mismatch repair-deficiency syndrome (CMMR-D) are characterised by early occurrence of colon cancer, haematological malignancies, and brain tumors (malignant gliomas, high-grade gliomas) in childhood, adolescence, and early adulthood. High mutational tumor burden is typical of glioblastoma in CMMR-D patients and could be a reason why this type of glioblastoma responds well to immunotherapies, including those that employ checkpoint inhibitors.

OBSERVATION

We describe a case of an adolescent with CMMR-D that had been genetically proven by whole exome sequencing (c.2T>A/p.M1K and c.2521delT/p.W841fs PMS2 gene mutation). The patient presented successively with colon cancer and glioblastoma with a high mutational burden. The individualized glioblastoma therapy was based on the biological tumor profile and included immunotherapy with a combination of vaccination with autologous dendritic cells producing IL-12 and nivolumab, in addition to radiotherapy with metronomic temozolomide. The patient is still alive 21 months after the initial glioblastoma diagnosis and shows a complete therapeutic response documented by repeated magnetic resonance examinations.

CONCLUSION

Individuals with CMMR-D should be regularly examined using established algorithms. Whole body magnetic resonance imaging can play a key role, because it enables the early diagnosis of malignancy during the asymptomatic period. Malignancies in CMMR-D patients usually exhibit a hypermutated genotype and respond to immunotherapy. Conventional glioblastoma therapy is only palliative. Patients can benefit from an individualized therapeutic plan based on the tumor biological profile. Extensive molecular analysis of the tumor tissue is necessary. Key words hereditary cancer predisposition syndromes - glioblastoma - whole exome sequencing - immunotherapy - vaccines - checkpoint inhibitors This study was supported by the research project of the Czech Ministry of Health AZV 16-33209A (Next generation sequencing and express profiling as diagnostic tools for personalized therapeutic plans in children with solid tumors). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 26. 9. 2018 Accepted: 18. 11. 2018.

Molecular Classification of Medullobastomas by Whole Genome Expression Profiling

BACKGROUND

Medulloblastoma (MB) is the most common malignant tumour of the central nervous system in children. MB is considered to be high risk tumour propensity to metastasize. In the Czech Republic, approximately 10-12 children are affected annually by this tumour. Recent progress in molecular diagnostics helps to refine the diagnosis and estimate clinical prognosis of the disease. Currently, MBs are subclassified into WNT-activated, SHH-activated, group 3, and 4 based on molecular pathways that drive their tumorigenesis. Each subtype differs in its histopathology, clinical features, genomic changes and gene expressions. The aim of our study is to classify patients MBs into four basic molecular groups and compare our results with published data.

MATERIAL AND METHODS

In our study we analysed expression profiles using Affymetrix GeneChip Human Gene 1.0. ST Array (Thermo Fisher Scientific, MA, USA). As input material RNA extracted from the fresh frozen tissue was used. Molecular classification based on the method established by P. Northcott in 2011 was performed.

RESULTS

From April 2015 to February 2019, 21 patients with MBs were included in our study. Median age of the patients at the time of diagnosis was 6 years, 14 boys and 7 girls were enrolled. Gene expression profiling and molecular classification of MBs was performed. Based on this methodology, we found the most frequently represented subgroup of MB was group 4 (9 patients, 43%), followed by group 3 (5 patients, 24%), SHH-activated MB (4 patients, 19%) and the least represented subgroup was WNT-activated MB (3 patients, 14%). Results of molecular subgroup classification of MBs were successfully correlated with histopathological findings and other molecular-genetic examinations.

CONCLUSION

Molecular classification of MBs has been established in our institution allowing better understanding of this heterogeneous disease and helping clinicians in therapeutic planning in affected patients. This work was supported by the Czech Ministry of Health grant No. 16-33209A. All rights reserved.  he authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 1. 3. 2019 Accepted: 4. 3. 2019.

Analysis of Blood Plasma MicroRNAs to Enable Identification of Patients with Pancreatic Ductal Adenocarcinoma Who Will Benefit from Surgical Resection

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is the most common malignancy of pancreas, characterized by extremely poor prognosis largely due to problem with early diagnosis and lack of progress in personalization of therapy. Of all available treatment strategies, radical surgical resection of the tumour in its early stage remains the only possibility how to reach long-term survival. However, even a technically perfect surgical resection may still not provide a survival benefit for all PDAC patients. Appropriate selection of patients for surgical resection is one the important medical needs in management of PDAC patients.

MATERIAL AND METHODS

To this study we enrolled 24 PDAC patients who underwent surgical resection and preoperatively collected their blood plasma specimends. Patients were divided into to two prognostic groups according to their overall survival - 12 patients with poor prognosis (median overall survival 10 months) and 12 patients with good prognosis (median overall survival 25 months). Small RNA sequencing technology was applied to screen for microRNAs (miRNA) with differential levels between both PDAC patients group. cDNA libraries were prepared using QIAseq miRNA Library Kit (Qiaqen) and sequencing by NextSeq500 instrument (Illumina).

RESULTS

When miRNA expression profiles of the PDAC patients from good and poor prognostic groups were compared, 61 miRNAs were identified to have significantly different plasma levels between the two groups (p < 0.05). A total of 21 miRNAs showed increased expression and 40 miRNAs showed decreased expression in a group of patients with poor prognosis compared to patients with good prognosis.

CONCLUSION

This study demonstrated differences in miRNA expression profiles in preoperative plasma specimens of PDAC patients with short and long overall survival. Our observations indicate that after independent validations plasma miRNAs might become useful biomarkers for identification of PDAC patients having clinical benefit from surgical resection of the tumour. This work was supported by Czech Ministry of Health, grant No. 16-31314A. All rights reserved. The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 8. 3. 2019 Accepted: 9. 3. 2019.

Utilization of Next Generation Sequencing in Analysis of Circulating MicroRNAs as Predictive Biomarkers for Patients with Locally Advanced Rectal Carcinoma

BACKGROUND

MicroRNAs (miRNA) are short non-coding RNAs involved in post-transcriptional regulation of gene expression. MiRNAs are essential regulators of both physiological processes as of pathogeneses of many diseases, and their dysregulation was observed in many malignancies including rectal cancer. Circulating miRNAs presented in blood plasma could be potential candidates for non-invasive predictive biomarkers of the response of patients with locally advanced rectal cancer to chemoradiotherapy. Presented study aims to evaluate the potential of next-generation sequencing in the analysis of circulating miRNAs.

MATERIAL AND METHODS

MiRNA expression profiles were done using samples of RNA isolated from blood plasma collected during TNM restaging and paired samples collected before initiation of neoadjuvant chemoradiotherapy. Sequencing libraries were prepared using kit which implements universal molecular indices that help to sensitively filter biological bias during data analysis. Sequencing data were processed by multidimensional biostatistical approaches.

CONCLUSION

We identified specific miRNA profile enabling to distinguish the patients accordingly to their response to chemoradiotherapy. This work was supported by the Czech Ministry of Health grant No. 16-31765A. The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 22. 2. 2019 Accepted: 27. 2. 2019.

Dynamic Changes in Circulating MicroRNA Levels in Liver Cancer Patients Undergoing Thermal Ablation and Transarterial Chemoembolization

BACKGROUND

Hepatic cancer patients who cannot undergo surgical resection of tumour are candidates for methods of interventional radiology - transarterial chemoembolization (TACE) or thermal ablative (TA) therapy. Both methods are causing characteristic changes in liver tissue (inflammatory immune response, hypoxia, elevated temperature, tissue destruction) which are accompanied with systemic secretion of cytokines or microRNAs (miRNAs). The aim of our study was to investigate whether the level of circulating miRNAs related to hypoxia (miR-21 and miR-210), liver injury (miR-122) and epithelial-mesenchymal transition (miR-200a) could reflect systemic effect of these intervention techniques.

MATERIALS AND METHODS

Study consisted of 10 primary hepatocellular carcinoma patients treated with TACE and 10 patients with liver metastases of colorectal cancer treated with TA. Thermal ablation was performed using the radiofrequency or microwave generator (RITA, Microsulis, AngioDynamics,Inc), for TACE drug eluting beads (DCBeads, Biocompatibles Ltd.) were used. Tumours were evaluated using RECIST (Response Evaluation Criteria in Solid Tumours), mRECIST (modified RECIST) criterion and volumetry. For all patients we determined concentrations of miRNA in blood plasma samples from four time points (before intervention, immediately after intervention, 24 hours after intervention, 1 week after intervention) using TaqMan® Assays and quantitative real time polymerase chain reaction method.

RESULTS

After both intervention techniques we observed changes in circulating miRNA levels. In TA cases we observed significant increase of miR-122 and miR-200a concentrations immediately after intervention, on the contrary in TACE we observed increase in miRNA concentration at time point 24 hours after intervention (miR-21, miR-210, miR-122, miR-200a). Increased concentration of circulating miRNA was followed by subsequent decline to initial level. These changes were consistent with presumed biological effect of TA and TACE on tumour tissue.

CONCLUSION

Data of this pilot study show potential usage of circulating miRNA for monitoring of systemic effect of thermal ablative and intraarterial therapies. This work was created at Masaryk University as part of the project MUNI/A/1574/2018 and it was supported by Czech Ministry of Health grants No. 15-32484A, 16-31765A and 16-31314A. The authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 1. 3. 2019 Accepted: 4. 3. 2019.

Effect of Tumor Size and p16 Status on Treatment Outcomes - Achievement of Complete Remission in Prospectively Followed Patients with Oropharyngeal Tumors

BACKGROUND

Oropharyngeal squamous cell tumors associated with human papillomavirus infection (p16 positive tumors) have better prognosis than p16 negative tumors regardless of the more advanced stage of the disease. Tumor volume (GTVt+n) is generally an important factor affecting treatment results of ionizing radiation. The aim of this prospective non-randomized study is to evaluate the effect of tumor volume on the (chemo)radiation treatment results in a group of patients with p16 negative and p16 positive oropharyngeal tumors.

PATIENTS AND METHODS

Patients with confirmed squamous cell tumor of the oropharynx of stages III and IV, according to the 7th version of the TNM (tumor-nodes-metastases) classification, were eligible for this study. The main exclusion criteria were palliative treatment, neoadjuvant chemotherapy or planned concomitant therapy with cetuximab. Patients were treated according to standardized protocols with curative intent. Primary tumor volume (GTVt) and involved nodes volume (GTVn) were obtained from radiotherapy planning system for further statistical analysis. The differences in tumor volumes between the groups according to p16 expression were assessed with subsequent testing of probability to achieve complete remission (CR) of the disease in both groups.

RESULTS

In total, 49 patients - 84% men, median age 60.5 years, 25 (51%) patients p16 positive, 40 (82%) underwent concomitant chemoradiotherapy. Median of GTVt in the whole patients group is 40.2 ccm, GTVn 11.78 ccm and median volume of the whole tumor burden (GTVt+n) 70.21 ccm (range 11.05-249). Median of GTVn was greater in the p16 positive cohort (p = 0.041). In the entire group, the median time to reach CR was 91 days (95% CI 86-107 days) from the end of radiotherapy. In the group of p16 negative patients, 14 achieved CR (61%) out of 23 patients, in p16 positive group 20 (80%) out of 25 patients (p = 0.111). P16 negative patients had a longer time to CR (p = 0.196, HR 1.58, 95% CI 0.79-3.18). None of the independently assessed volumetric parameters of the tumor (GTVt, GTVn, GTVt+n) affected CR in the p16 positive patients group, while there was a significant impact of the whole tumor burden (GTVt+n) in the p16 negative cohort (median 58.1 ccm in CR patients vs. 101.9 ccm, p = 0.018).

CONCLUSION

We have showed less GTVt+n dependence to achieve CR in p16 positive tumors in comparison with p16 negative tumors. Thus, p16 positive oropharyngeal squamous cell cancers should not be withdrawn from the curative treatment intent based on the greater GTVt+n. Key words oropharyngeal neoplasms - p16 status - treatment outcome - tumor burden - complete remission This work was supported by grant of the Ministry of Health of the Czech Republic AZV 15-31627A and by grant of the Ministry of Health of the Czech Republic - Conceptual development of a research organization (MMCI 00209805). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 2. 11. 2018 Accepted: 11. 11. 2018.

[Usage of Cerebrospinal Fluid for microRNA Analysis]

BACKGROUNDS

Deregulated levels of miRNAs, short noncoding RNAs associated with pathogenesis of many diseases, have been observed in cerebrospinal fluid (CSF). Therefore, the analysis of CSF miRNAs in patients affected by tumors of central nervous system (CNS) might help to develop new diagnostic platform enabling more precise diagnosis. Thus, in our study we tried to optimize methodical approaches to be used for miRNA detection as RNA isolation and selection of suitable technology for global high-throughput miRNA profiling.

MATERIAL AND METHODS

In the optimization phase of RNA isolation from CSF, various commercially available kits with different protocol modifications were compared. Two quantitative polymerase chain reaction panels and Next Generation Sequencing method were tested for selection of the most suitable method for miRNA comprehensive profiling.

RESULTS

The Urine miRNA Purification kit (Norgen) and Next Generation Sequencing was selected as the most suitable kit for RNA extraction from CSF and method for miRNA comprehensive profiling, resp.

CONCLUSION

We established a protocol for RNA isolation and miRNA comprehensive profiling in CSF clinical specimens.Key words: brain neoplasm - cerebrospinal fluid - microRNA The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. This study was supported by Ministry of Health of the Czech Republic, grant No. 15-34553A. All rights reserved.Submitted: 19. 3. 2018Accepted: 10. 4. 2018.

[Dysregulation of Long Non-coding RNAs in Glioblastoma Multiforme and Their Study Through Use of Modern Molecular-Genetic Approaches]

BACKGROUND

Glioblastoma (GBM) is the most frequent primary brain tumor characterized by an unfavourable prognosis despite multimodal therapy. Therefore, a lot of efforts and financial resources are dedicated to the research of new therapeutic targets and prognostic or predictive biomarkers. Long non-coding RNAs (lncRNAs) are regulators of gene expression which play a significant role in GBM pathology and, thus, present promising candidates.

MATERIAL AND METHODS

Our study included 14 patients with GBM and 8 patients with intractable epilepsy from whom we acquired brain tissues during surgical intervention. Ribosomal RNA depleted RNA was used for sequencing by NextSeq 500 instrument (Illumina). Statistical analysis evaluated 24,087 protein-coding and 8,414 non-coding RNAs and their sequential variants with non-zero reads per kilobase per million mapped reads (RPKM) at least in one sample. CLC Genomic Workbench was used for the alignment and target counts. Targeted downregulation of up-regulated ZFAS1, one of the identified lncRNA, level has been carried out by the transient transfection of specific small interfering RNA (siRNA) in GBM stable cell lines (A172, U87MG, T98G). The success of transfection and viability were analyzed in vitro using quantitative real time polymerase chain reaction and MTT assay, resp.

RESULTS

Statistical analysis has revealed 274 (p < 0.01) dysregulated lncRNAs in GBMs in comparison with non-tumor brain tissues. Moreover, the results have showed 489 dysregulated mRNAs (p < 0.0001) and 26 mRNAs (p < 0.000001). Transfection of ZFAS1 inhibitor led to successful downregulation of ZFAS1 expression level, although it did not have a significant effect on proliferation of GBM cells.

CONCLUSION

We described a significant dysregulation of lncRNAs and mRNAs in GBM tissue in comparison with non-tumor tissue. We also succesfully decreased expression level of ZFAS1, which in turn, however, had no impact on the viability of GBM cell lines.Key words: glioblastoma - long non-coding RNA - next-generation sequencing The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. This tudy was supported by Ministry of Health of the Czech Republic, grant No. 15-33158A. All rights reserved.Submitted: 19. 3. 2018Accepted: 10. 4. 2018.

[Urinary MicroRNAs as Potential Biomarkers of Bladder Cancer]

BACKGROUND

Currently, there are no urinary-based tumour markers with sufficient sensitivity and specificity to replace cystoscopy in the detection of bladder cancer (BCA). Urinary microRNAs are emerging as clinically useful class of biomarkers for early and non-invasive detection of urologic malignancies.

PATIENTS AND METHODS

In this study, 155 patients with BCA and 83 healthy controls were enrolled. Expression profiles of urinary miRNAs were obtained using Affymetrix miRNA microarrays and candidate miRNAs further validated in independent cohort using specific TaqMan assays and quantitative real-time polymerase chain reaction method.

RESULTS

Whole-genome profiling identified miRNA signature with significantly different concentrations in urine of BCA compared to controls (p < 0.01). In the independent validation phase of the study, three miRNAs were confirmed to have significantly higher levels in urine of patients with BCA in comparison with control groups (p < 0.0001). In addition, we observed significant decrease in two miRNAs (p < 0.01) concentrations in the urinary samples collected 3 months after surgery compared to pre-operative samples.

CONCLUSION

We identified and validated miRNAs to have significantly higher concentrations in urine of patients with BCA in comparison with controls. Our data have shown that urinary miRNAs could serve as sensitive and specific biomarkers enabling non-invasive detection of BCA.Key words: urinary microRNAs - biomarkers - bladder cancer The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. This study was supported by Ministry of Health of the Czech Republic, grant No. 15-31071A. All rights reserved.Submitted: 19. 3. 2018Accepted: 20. 3. 2018.

[Pilot Study on MicroRNAs as Biomarkers of Response to Sunitinib Treatment in Patients with Metastatic Renall Cell Carcinoma]

BACKGROUND

Renal cell carcinoma (RCC) accounts for 2-3% of all malignant tumours. Metastatic RCC (mRCC) is commonly treated with tyrosine kinase inhibitors (TKI). Effective TKIs administration can be achieved only by accurate prediction of therapeutical response. Therefore, the aim of this study was to analyse papers concerning predictive potential of microRNA (miRNA).

MATERIAL AND METHODS

We chose seven candidate miRNAs and analysed their expression on 44 patients divided into cohort with poor and good response to sunitinib treatment. Patients were divided into two groups according to progression-free survival. RNA from tissue samples was isolated and expression of selected miRNAs was measured using quantitative PCR with miRNA-specific TaqMan probes.

RESULTS

We successfully validated two miRNAs to be differentially expressed in responding and non-responding patients to sunitinib treatment. Other analysed miRNAs have not shown predictive potential.

CONCLUSION

From miRNAs studied so far, two miRNAs had predictive value according to present study.Key words: microRNA - renal cell carcinoma - sunitib The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Supported by Ministry of Health of the Czech Republic, grant No. 15-34678A. All rights reserved.Submitted: 19. 3. 2018Accepted: 20. 3. 2018.

[MicroRNAs in Prediction of Response to Radiotherapy in Head and Neck Cancer Patients - Pilot Study]

BACKGROUND

Radiotherapy plays a key role in the treatment of squamous cell head and neck cancers (HNSCC). The effectivity of radiation therapy is often limited by radioresistance of these tumours. microRNAs (miRNAs) are endogenous, evolutionary conserved, small non-coding RNAs involved in regulation of cellular processes associated with radioresistance. The objective of this study was to identify miRNA profile enabling to predict the radiation treatment outcomes in HNSCC patients.

MATERIAL AND METHODS

The retrospective study included HNSCC patients who underwent a definitive radiotherapy. Patients were divided into two groups according to loco-regional control (LRC) as follows - short LRC (n = 22; median 5.1 months (min. 1.3, max, 18.6)) vs. long LRC (n = 21; 60.4 (min. 46.8, max. 98.8)) group. Global miRNA expression profiles were obtained by use of Affymetrix microarray technology (GeneChip miRNA 4.0 Array).

RESULTS

We identified 24 miRNAs to be significantly associated with LRC (p < 0.05), all of these miRNAs were upregulated in patients with short LRC. Out of these miRNAs, 12 miRNAs with p < 0.025 and 4 miRNAs with p < 0.01 have been identified.

CONCLUSION

miRNAs seems to be promising as potential biomarkers predicting radiotherapy treatment outcomes in patients with HNSCC.Key words: microRNAs - radiotherapy - head and neck cancer The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Supported by Ministry of Health of the Czech Republic, grant No. 15-31627A. All rights reserved.Submitted: 19. 3. 2018Accepted: 20. 3. 2018.

[MicroRNA Analysis for Extramedullary Multiple Myeloma Relapse]

INTRODUCTION AND AIMS

Multiple myeloma (MM) is the second most common hematooncological disease. Patient survival has been greatly improved by the introduction of new drugs into clinical practice, but survival is negatively affected by the so-called extramedullary relapse (EM), caused by the loss of plasma cell dependence on the bone marrow microenvironment and their migration out of the bone marrow. The nature and causes of this process are currently unclear. MicroRNAs (miRNAs) are short, non-coding RNA molecules involved in many physiological and pathological processes. Their significance in the pathogenesis of MM has been demonstrated by several studies. We assume that they are also involved in the development of the EM. The aim of this study was to analyze different miRNA expression between MM and EM patients.

MATERIAL AND METHODS

Using next generation sequencing, we analyzed 39 samples of bone marrow cells from MM patients at diagnosis and 9 bone marrow plasma samples of EM patients.

RESULTS

In total, 2,278 miRNA were sequenced, but only 658 miRNAs were analyzed as they were expressed in all samples and had at least 20 reads. Expression data were generated using the Chimira tool from fastq data. All sequences were mapped using miRBase v20. Further analyses were performed using the R/Bioconductor package. The Bayesian procedure was used for normalization of expression. P values were adjusted using the Benjamini-Hochberg method. Analysis found 10 miRNA (p < 0.0005) that are statistically significantly expressed in EM vs. MM patients - these are miR-26a-5p, miR-26b-5p, miR-30e-5p, miR-424-3p, miR-503-5p, miR-767-5p, miR-105-5p, miR-5695-5p, miR-450b-5p and miR-92b-3p. These miRNAs will be further verified by qPCR method on a larger set of MM and EM patients.

CONCLUSION

Our pilot study has shown that there are differentially expressed miRNAs between MM and EM patients.Key words: multiple myeloma - microRNA - carcinogenesis - next generation sequencing The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papersThis work was supported by grant MZ ČR AZV 17- 29343A. Submitted: 17. 3. 2018Accepted: 20. 3. 2018.

Systemic administration of miRNA mimics by liposomal delivery system in animal model of colorectal carcinoma

MiRNAs are important regulators of gene expression and changes in their levels are linked with various pathological states, including solid tumors. MiR-215 has been identified as a tumor suppressor in colorectal cancer (CRC). Following our previous in vitro and in vivo experiments, the aim of this project was to study the possibility of increasing the levels of miR-215 in tumor cells by systemic administration of miRNA mimics in liposomal delivery system in vivo. By subcutaneous xenotransplantation of human cancer cells to NSG mice, CRC model was established. The treatment (miR-215 mimics in liposomes [20 and 40 microg/mouse], control oligonucleotide in liposomes, or saline) was administered repeatedly by i.v. injection via tail-vein. Animals were sacrificed, tumor were dissected and measured by a caliper. Expression of miR-215 in tumors, lungs and liver was quantified by RT-PCR. There was no significant differences in tumor volume and miR-215 expression between all three treatment groups. Therefore, the decrease in tumor volume was not achieved. By comparing the levels of miR-215 in lungs, liver and tumors after the treatment, we suggest that the liposomes are accumulated in the lungs and do not concentrate sufficiently in the tumor site to exert significant tumor-suppressive effect.

[Involvement of PIWI-interacting RNAs in Cancerogenesis via the Regulation of Gene Expression]

BACKGROUND

In the past few years, a number of studies have suggested that small non-coding RNAs could be promising diagnostic, prognostic and predictive biomarkers in oncology. Recently, small RNAs interacting with PIWI proteins (piRNAs) have been described. These small RNAs regulate gene expression at transcriptional and post-transcriptional levels; however, they appear to be specifically involved in silencing the transposable elements LINE and SINE and are thus considered to contribute to genomic stability. Furthermore, piRNAs participate also in other important biological processes, such as gametogenesis, chromosome segregation, and stem cell self-renewal. Although their expression was first noted in germ line cells, they are now known to be present in all tissue types and their expression is highly tissue-specific. In addition, piRNA expression is dysregulated in tumor tissues. Nevertheless, the exact function of these molecules in cancerogenesis is not known. Recently, free circulating piRNAs were reported to be stably present in body fluids, suggesting that they could serve as promising noninvasive biomarkers to enable early diagnosis, therapy response prediction, and accurate prognosis prediction of cancer patients.

AIM

The aim of this review is to summarize current knowledge about piRNA biogenesis and their functions in the regulation of gene expression and transposons silencing. In addition, the review focuses on piRNAs that show dysregulated expression in different types of cancers and that could serve as potential diagnostic biomarkers and/or therapeutic targets.Key words: PIWI-interacting RNAs - piRNA - biogenesis - cancer - transposon silencing - biomarkers - therapeutic targetsThe results of this research have been acquired within CEITEC 2020 (LQ1601) project with financial contribution made by the Ministry of Education, Youths and Sports of the Czech Republic within special support paid from the National Programme for Sustainability II funds.The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 23. 11. 2016Accepted: 5. 12. 2016.

[Current Possibilities for Predicting Responses to EGFR Blockade in Metastatic Colorectal Cancer]

BACKGROUND

The combination of modern systemic chemotherapy and anti-EGFR monoclonal antibodies improves overall survival and quality of life for patients with metastatic colorecal cancer. By contrast, the addition of anti-EGFR therapy to the treatment regime of resistant patients may lead to worse progression-free survival and overall survival. Therefore, identifying sensitive and resistant patients prior to targeted therapy of metastatic colorecal cancer is a key point during the initial decision making process. Previous research shows that primary resistance to EGFR blockade is in most cases caused by constitutive activation of signaling pathways downstream of EGFR. Of all relevant factors (mutation of KRAS, NRAS, BRAF, and PIK3CA oncogenes, inactivation of tumor suppressors PTEN and TP53, amplification of EGFR and HER2, and expression of epiregulin and amphiregulin, mikroRNA miR-31-3p, and miR-31-5p), only evaluation of KRAS and NRAS mutations has entered routine clinical practice. The role of the other markers still needs to be validated. The ongoing benefit of anti-EGFR therapy could be indicated by specific clinical parameters measured after the initiation of targeted therapy, including early tumor shrinkage, the deepness of the response, or hypomagnesemia. The accuracy of predictive dia-gnostic tools could be also increased by examining a combination of predictive markers using next generation sequencing methods. However, unjustified investigation of many molecular markers should be resisted as this may complicate interpretation of the results, particularly in terms of their specific clinical relevance.

AIM

The aim of this review is to describe current possibilities with respect to predicting responses to EGFR blockade in the context of the EGFR pathway, and the utilization of such results in routine clinical practice.

[Immunotherapy for the Prevention and Treatment of Breast Cancer]

The immune system is believed to play a dual role in carcinogenesis. On one hand, it could prompt tumorigenesis and cancer progression, on the other hand, it has the capacity to eradicate tumor cells. There has been an evidence of natural immunogenicity in breast cancer and we have also witnessed several attempts to stimulate non-specific antitumor immune response (Coleys toxin, BCG vaccine etc.). New technologies and further knowledge of molecular basis of immune system and its function encouraged the development of effective immunotherapy capable of inducing a solid antitumor activity. These agents appear promissing in the prevention and therapy of breast carcinoma as well. The assumption is based on the results of several antitumor vaccine trials targeted against HER2, MUC1, CEA and mammaglobin-A, as well as immune checkpoint inhibitors (e.g. CTLA-4, PD-1/ PD-L1, LAG3). With regards to different mech-anisms of action of these agents, their combination might bring about synergistic antitumor effects. Nonetheless, monoclonal antibodies and cytostatic agents already approved for breast cancer treatment might be exploited for their immunomodulation effect as well. This article addresses prospects for immunotherapy of breast carcinoma in detail.

[The role of microRNAs in molecular pathology of esophageal cancer and their potential usage in clinical oncology]

MicroRNAs are an abundant class of noncoding RNAs (approx. 18- 25 nucleotides in length) that suppress translation through binding to their target mRNAs, eventually leading to mRNAs degradation. Sequences of these endogenous RNA molecules are highly conserved, even among unrelated species, indicating their involvement in basic bio-logical processes, such as development, differentiation, proliferation or apoptosis. MiRNAs also participate on regulation of cancer stem cell functioning, immune system and malignant transformation. This review provides a comprehensive overview of miRNAs functions in esophageal cancer, their roles in key pathogenetic pathways and disease development, as well as their potential usage in clinical routine as bio-markers improving dia-gnosis, prognosis and prediction of therapeutic response. Through regulation of signaling pathways important in malignant transformation, miRNAs present also promising therapeutic targets.

[The role of MicroRNAs in the pathophysiology of neuroblastoma and their possible use in diagnosis, prognosis and therapy]

Neuroblastoma (NBL) is a typical childhood tumor developing from the precursor cells of the sympathetic nervous tissue and accounting for approximately 7% of total malignancies in pediatrics and 15% of deaths associated with this malignancy. MicroRNAs (miRNAs) are small single-stranded RNA molecules that are involved in posttranscriptional regulation of gene expression, whereas the pathophysiology of neuroblastoma tumor growth involves both upregulation of the protooncogenic miRNAs as well as downregulation of the tumor-suppresor ones. Comparison of the expression profiles of miRNAs in specific subtypes of neuroblastoma seems to be a useful tool adding to the classification of the diseases, and the assessment of the levels of specific miRNAs may be useful for estimation of the individual treatment response as well as prognosis of the patient. This paper provides the basic review of the studies focused on the role of miRNAs in pathogenesis of neuroblastoma and provides a survey of current/ possible use of these miRNAs in diagnostics, therapy or prognosis estimation in the neuroblastoma patients.

[Epidemiological and clinico-pathological characteristics of patients with renal carcinoma: a single institution analysis of 544 cases]

BACKGROUND

The incidence of renal cell carcinoma in the Czech Republic is one of the highest in the world. Curative treatment is still possible only surgically, while in the palliative treatment, partial success was reached using targeted therapies. While prognostic factors and models are commonly used in clinical practice, unfortunately, predictive biomarkers have not been found. The aim of our study was to verify the validity of selected prognostic factors on a consecutive patient cohort from the Czech population.

PATIENTS AND METHODS

The patient cohort consisted of 544 patients with RCC diagnosed and/or treated at our institute from 2003 to 2010. Individual clinical and histological prognostic factors and Heng prognostic model were validated.

RESULTS

Median time of follow-up for our cohort was 42 months (range 0.3-326 months), median age at diagnosis was 62 years, and almost 64% of patients were men. Distribution of clinical stages was as follows: 46.5% of I, II. 10.7%, III. 13.1%, IV. 20%. 26.4% of patients in stage I-III relapsed. We diagnosed mainly clear cell (84.6%) and papillary carcinoma (9.2%). Initially, 95.8% of patients underwent surgical treatment, systemic adjuvant and palliative treatment was applied in 3.7 and 37.7% of patients, respectively. Palliative targeted therapy was received by a total of 163 patients (30%). In first-line targeted therapy, the following median TTP was reached (in months): 10.8 for sunitinib, 6.3 for sorafenib and 5.2 months for immunotherapy. The most significant prognostic factors (p < 0.00001) were: stage of disease (HR = 9.61), size of the primary tumor (HR = 5.83), lymph nodes (HR = 8.26), presence of sarcomatoid tumor sections in the tumor (HR = 7.29), and tumor grade (HR = 4.0). Besides these, we also confirmed the prognostic importance of presence of eosinophilic granulations in the tumor (HR = 1.91, p = 0.02). When applying the Heng prognostic model, we achieved similar results for patients treated with targeted therapies.

CONCLUSION

The obtained epidemiological and clinico-pathological data are consistent with previously published data. These prognostic factors can be used for a differentiated approach to patients with RCC, both for establishing follow-up plan for patients after surgery as well as indication for targeted therapies.

[New knowledge of the pathogenesis of Crohn's disease]

Crohns disease is a complex chronic inflammatory disease of the gastrointestinal tract with multifactorial pathogenesis. Over the recent years, there has been rather a sharp increase in the incidence of Crohn's disease and, even though this disease had been known for some time, the cause remains unknown. Studies exploring genetic basis of Crohn's disease have provided new knowledge of the pathogenesis of this disease, suggesting that this may be associated with a failure of mechanisms behind symbiosis of gut microflora and intestinal mucosal immune system. Crohn's disease seems to be caused by inadequate immune response to intestinal flora in genetically predisposed individuals. Crohn's disease has been linked to a number of genes. Many of them are related to the modulation of non-specific immune response, defects of which are considered to be key in Crohn's disease pathogenesis. The aim of this review paper is to summarize the new knowledge on the pathogenesis of Crohn's disease at the level of polymorphisms of the NOD2, ATG16L1 genes and the IL23-Th17-lymfocytes signalling pathway genes and to consider further research directions in this disease.

[Long non-coding RNAs and their relevance in cancer]

A major portion of the eukaryotic genome is occupied by DNA sequences; transcripts of these sequences do not code for proteins. This part of the eukaryotic genome is transcribed in a developmentally regulated manner or as a response to external stimuli to produce large numbers of long non-coding RNAs (lncRNAs). Genome-wide studies indicate the existence of more than 3,300 lncRNAs. Long non-coding RNAs are tentatively defined as molecules of ncRNAs that are more than two hundred nucleotides long. Due to the complexity and diversity of their sequences, progress in the field of lncRNAs has been very slow. Nonetheless, lncRNAs have emerged as key molecules involved in the control of transcriptional and posttranscriptional gene regulatory pathways. Although limited numbers of functional lncRNAs have been identified so far, the immense regulatory potential of lncRNAs is already evident, emphasizing that a genome-wide characterization of functional lncRNAs is needed. The fact that many lncRNAs are deregulated in various human cancers, together with their functional characteristics, implies their eminent role in carcinogenesis. In this review, we summarize novel classes of lncRNAs, describe their biological functions emphasizing their roles in tumor biology and translational oncology research.

[Triple-negative breast cancer: analysis of patients diagnosed and/or treated at the Masaryk Memorial Cancer Institute between 2004 and 2009]

BACKGROUND

Triple-negative breast cancer (TNBC) represents a heterogeneous group of breast cancers that do not express ER-α, PgR and Her-2 receptors. Generally, these tumors are aggressive and more common in younger women, in which an association of TNBC with mutations in the BRCA1 gene was documented. The aim of our study was to create a representative group of patients with TNBC, which could be analyzed and the data gathered to build basic epidemiological, molecular and clinical characteristics of Czech patients with TNBC.

PATIENTS AND METHODS

We performed basic clinical-pathologic correlations in a group of 335 patients diagnosed and/or treated for TNBC at the Masaryk Memorial Cancer Institute between 2004 and 2009. We also performed immunohistochemical examination of expression of cytokeratin 5/6, cytokeratin 14 and EGFR to identify the basal-like subset of TNBC.

RESULTS

The median age of patients with TNBC was 56 years, range 25-88 years. A total of 9.25% of TNBC cases were diagnosed in patients under the age of 34, and another 15.22% of cases were in the age group of 35 to 44 years. 'Basal-like' carcinomas accounted for 75% of TNBC. We confirmed the aggressive nature of this disease: in the follow-up period we observed a relapse in 25% of patients: 55% of deaths due to disease progression occured within 2 years after diagnosis of the disease. Treatment strategies include chemotherapy, in most cases (88.4%). Chemotherapy was mostly based on regimens with anthracyclines or in combination with taxanes. The most important negative prognostic factors in relation to OS (disease specific OS) were: higher clinical stage (p < 0.0001), pN - positive status (p < 0.0001), high proliferative activity (as measured by Ki-67, cut-off 50%, HR = 0.4740, p = 0.0411) and positive expression of CK5/6 (HR = 0.4274, p = 0.0338). In relation to DFS, the negative prognostic significance was found for these factors: higher clinical stage (p < 0.0001), pN positive status (p < 0.0001), high proliferative activity (Ki-67, cut-off 50%, HR = 0.04993, p = 0.0240). DFS was longer in patients with a higher number of applied cycles of anthracycline-based chemotherapy (> 4 cycles, HR = 1.7273, p = 0.0467).

CONCLUSION

TNBC is an aggressive form of breast cancer, which may occur in patients of all ages, but more frequently in younger patients. Only early detection of disease and intensive treatment gives a high chance of cure. Unfortunately, no reliable predictive factors have been identified so far. Better therapeutic results can be expected from targeted therapy.

[Multimodal treatment of glioblastoma multiforme: results of 86 consecutive patients diagnosed in period 2003-2009]

BACKGROUNDS

Glioblastoma multiforme is the most common malignant primary tumor of the brain in adults. Standard therapy consists in maximal surgical resection and adjuvant concurrent chemoradiotherapy and adjuvant therapy with temozolomid. This approach improves survival in comparison with postsurgical radiotherapy alone.

PATIENTS AND METHODS

Consecutive patients with histologically confirmed glioblastoma multiforme in the period from January 2003 to December 2009 underwent postoperative radiotherapy (1.8-2.0 Gy/d, total of 60 Gy) plus concurrent daily chemotherapy (temozolomide 75 mg/m2/d), followed by 6 cycles of temozolomide (150 to 200 mg/m2 for 5 days, every 28 days) and were analyzed retrospectively. The primary end point was to describe the correlation between known clinical factors, treatment and progression free survival (PFS) and overall survival (OS). We assessed the toxicity and safety of the chemoradiotherapy.

RESULTS

Eighty-six patients (median age, 56 years; 60% male) were included. Most of them (> 80%) were of performance status (PS) 0-1 at the beginning of chemoradiotherapy. Total macroscopic resection was performed in 20% of the patients, subtotal in 65%, partial in 9%, and just biopsy in 6%. Median PFS was 7.0 months (2.0-35.5), median OS was 13.0 months (2.5-70). Postoperative performance status (PS), the extent of resection, and administration of planned treatment without reduction had statistically significant influences on PFS and OS. Median PFS and OS were 22.0, 7.0 and 6.0 months for PFS (p = 0.0018) in patients with PS O, 1 and 2 respectively and 32.0, 13.0 and 9.0 months for OS (p = 0.0023). Patients with total removal of tumor had longer PFS (14.0 vs 6.0 months, HR = 0.5688; p = 0.0301) and OS (23.0 vs 12.0 months, HR 0.4977; p = 0.0093), as did patients without dose reduction of radiotherapy and/or chemotherapy. Patients with radiotherapy dose of over 54 Gy had PFS 8.0 vs 3.0 months (HR = 0.3313; p = 0.0001) and OS 15.0 vs 5.0 months (HR = 0.1730; p < 0.0001). Similarly, treatment with concurrent chemotherapy for more than 40 days was also important: PFS 8.0 vs 5.0 months (HR = 0.5300; p = 0.0023) and OS 17.0 vs 9.5 months (HR = 0.5943; p = 0.0175). Age, gender and position of tumor had no significant influence. Treatment-related hematology toxicity grades 3 and 4 occurred relatively often: thrombocytopenia (9%), leukopenia (6%), neutropenia (6%) and lymphopenia (25%). Thrombo-embolic events were dominant in non-hematology toxicity. Serious toxicity occurred mainly in the subgroup of patients with PS 2. Treatment of progression was useful in selected patients. Second surgery was of the most benefit (OS 24.0 vs 12.5 months, HR = 0.5325; p = 0.0111).

CONCLUSION

Postoperative performance status, extent of resection, successful administration of the majority of planned concurrent chemoradiotherapy and possibility of surgical treatment at the time of recurrence correlate with better prognosis for our patients with glioblastoma. Our experience indicates that performance status should be the main factor in decisions about treatment intensity. Treatment of malignant glioma requires a multidisciplinary team.

[EGFR tyrosine kinase inhibitors as a targeted therapy for bronchioloalveolar carcinoma of the lung: a case report of a clinically prompt and intensive response and literature review]

INTRODUCTION

Bronchioloalveolar carcinoma (BAC) is an adenocarcinoma belonging to non-small cell lung carcinomas (NSCLC) that, in addition to its morphology and endobronchial spread, presents with certain specific clinical characteristics: greater incidence in women, non-smokers and younger patients, presence of malignant bronchorrhea and lower susceptibility to conventional cytostatic therapies in comparison to other subtypes of NSCLC. On the other hand, nonmucinous type of BAC may show better therapeutic response to targeted therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI) erlotinib or gefitinib, as it is 5 times more frequently a carrier of EGFR gene mutations compared to conventional lung adenocarcinomas.

CASE DESCRIPTION

We present a case of a 41 years old man, non-smoker for the last 5 years, who was diagnosed with a pneumonic form of nonmucinous bronchioloalveolar carcinoma. Metastases to regional and distant lymph nodes and massive involvement of skeleton with infiltrations in the bone marrow were present at the diagnosis. During the first line palliative chemotherapy with combination regimen of carboplatin and paclitaxel, the disease progressed significantly and the patient's condition deteriorated (performance status (PS) 3, severe dyspnoea at rest, malignant bronchorrhea). Subsequently, administration of erlotinib was initiated based on a series of case studies describing good response of BAC to treatment with EGFR TKI. An evident improvement of the patient's condition was observed as early as 4 days of administration, together with regression of peripheral lymphadenopathy. Nearly complete disappearance of pulmonary infiltrates was observed after 30 days of therapy, with the patient becoming asymptomatic, PS 0. Molecular genetics confirmed the tumour phenotype to be highly responsive to EGFR TKI therapy. The tumour contained EGFR mutation in exon 19 (in-frame L747-753insS deletion) and wild-type K-ras. Disease relapse in the liver occurred 6 months later confirming disease progression. Further treatment remained ineffective despite brief stabilisations of liver enzyme progression following repeated administration of pemetrexed and gefitinib. The patient died 12 months after the diagnosis.

CONCLUSIONS

Our case confirms the importance of targeted therapy when treating tumours of an appropriate phenotype. Such treatment may have prompt and intensive effect that may reverse the course of the disease even in patients with poor overall health status.

[DNA and microRNA microarray technologies in diagnostics and prediction for patients with renal cell carcinoma]

Renal cell carcinoma accounts for approximately 3% of adult cancers and has the highest lethality of urological malignancies. Research focusing on carcinogenesis and development of renal cell carcinoma has led to the identification of the key signalling pathways and consequently targeted cancer therapy which improves time to progression or overall survival of renal cell carcinoma patients. Today, microarray technologies are some of the most efficient methods used in gene expression studies. Through one microarray experiment we can simultaneously determine the expression of thousands of genes, thus facilitating research of examined biological models. The most frequently used of the microarray technologies are DNA microarrays enabling global analysis of the mRNA (messenger RNA) expression, while recently, microarray platforms modified to detect short non-coding RNAs (microRNAs) have been employed (microRNA microarrays). MicroRNAs significantly affect the behaviour of tumour cells by post-transcriptional regulation of the gene expression. In the research into renal cell carcinoma, microarray technologies have been applied in more than twenty studies over the past five years. These papers describe the potential of microarrays to distinguish tumour tissue from normal renal parenchyma, to classify renal cell carcinomas according to histological subtypes, to identify expression profiles predicting metastasizing in primary renal tumours, and to determine the prognosis of particular renal cell carcinoma patients. The aim of this review is to summarize the results from microarray studies of renal cell carcinoma realized to date and to present their potential usage in diagnostic and therapeutic protocols.

[Possibilities of resistance prediction to neoadjuvant concomitant chemoradiotherapy in the treatment algorithm of patients with rectal carcinoma]

BACKGROUNDS

Neoadjuvant concomitant chemoradiotherapy has become a standard treatment of locally advanced rectal adenocarcinomas (LARA). It leads to shrinkage of the tumor mass and subsequently to an increase in complete resections (R0 resections), increasing a feasibility of sphincter-sparing intervention avoiding colostomy. It is based on concurrent application of fluoropyrimidines (5-fluorouracil, capecitabine) and radiotherapy (45 - 50,4 Gy). It shows less acute toxicity and improves local control rate in comparison to adjuvant treatment. Unfortunately, neoadjuvant chemoradiotherapy is not beneficial for all patients. The treatment response ranges from a complete pathological remission (pCR, ypT0ypN0) to a resistance. It is reported that cca 15 percent of patients with advanced rectal cancer show pCR which is indicative of improved long-term prognosis.

DESIGN

The following is a review of the significance of neoadjuvant concomitant chemoradiotherapy in the treatment algorithm of patients with LARA and summary of potentional clinical-pathological and molecular markers of response prediction to neoadjuvant therapy. The most important clinical studies concern serum tumor markers levels, clinical lymph node classification. The components of the carcinogenic pathways are explored, including oncogenes, tumor supressor genes, microsatellite instability (MSI) and potentional markers involved in apoptosis, angiogionesis, proliferation as well as metastasis and invasion, are reviewed. Finally, the role of specific enzymes associated with the metabolism of fluoropyrimidines are examined.

CONCLUSIONS

No one marker has been consistently identified as clinically applicable. Studies designed to determine the potentional markers are hampered by various techniques as well as tumor heterogenity and recent scientific approach--studying individual molecular markers. Gene expression profiling analysis of multiple genes from the same tumor is becoming reality. We suppose that this assessment will lead in future in finding combination of markers for predicting prognosis and response to therapy in rectal cancer.

[Gene expression profiling in prediction of tumor response to neoadjuvant concomitant chemoradiotherapy in patients with locally advanced rectal carcinoma: pilot study]

BACKGROUND

Neoadjuvant concomitant chemoradiotherapy has become a standard treatment of locally advanced rectal adenocarcinomas (LARA). It can reduce tumor volume, thus increases a feasibility of sphincter-sparing surgery, shows less acute toxicity, improves local control rate. It is based on fluoropyrimidines (5-fluorouracil, capecitabine) with concurrent radiotherapy. The aim of the study was to evaluate the capability of gene expression method to identify nonresponders (NR) pretherapeutically.

METHODS AND RESULTS

17 patients with LARA, clinical stage II, III according to IUCC were enrolled into our pilot study. Response to therapy was determined clinically by transrectal ultrasonography and CT/MRI before and after therapy and histopathologically by TRG (tumor regression grade) according to Mandard. Patients with TRG 1-2 were included to responders group (R) and patients with TRG 4-5 composed NR group. Gene expression levels of 440 genes were obtained by low-density oligonucleotide microarrays. Gene expression data analysis based on SAM (Significance Analysis of Microarrays) and t-test methods identified 8 genes (RB1, RBBP4, HYOUI, JUNB, MDM4, CANX, MMP2, TCF7L2) significantly upregulated in NR.

CONCLUSIONS

Validation of identified changes on the mRNA level (Real-Time PCR) and on protein level (immunohistochemistry) is ongoing. We suggest that low-density oligonucleotide microarray technology could contribute to individualize the therapy of patients with LARA.

[Involvement of microRNAs in cancer biology and possibilities of their application to diagnostic and predictive oncology]

MicroRNAs (miRNAs) are large class of non-coding RNAs that post-transcriptionally regulate gene expression. Their ability of translational repression applied for example on oncogenes or tumor-suppressor genes indicates involvement of miRNAs in multi-step carcinogenesis. Evidences of miRNAs linkage to biological processes like apoptosis, proliferation, differentiation and cell survival are rapidly accumulating. Approximately 50% of miRNAs are located at fragile sites of chromosomes or regions known to be amplified or deleted in human cancer. That is why, non-coding miRNAs seem to be another level of genetic information which regulation is altered or lost during neoplastic growth. Expression profiles of miRNAs are successfully used for molecular classification, more exact diagnosis and prognosis of human cancers and reached analogical analytical characteristics like studies based on DNA micro-arrays technology and profiling of coding transcripts. In this review we attempt to introduce basic knowledge of miRNAs biogenesis and biological functions and in particular summarise reports focused on miRNAs in oncology research area.