Search

Introduction. Epidermal growth factor receptor (EGFR) is a transmembrane protein of the receptor tyrosine kinase family that is activated in various cancers (non-small cell lung cancer, colorectal cancer, head and neck tumors). In glial brain tumors, increased EGFR expression levels are characteristic of the most aggressive subtype, glioblastoma. Frequent structural changes of EGFR in glioblastoma are amplification of the chromosome region where the EGFR gene is located, point mutations, as well as deletion of exons 2–7 of the EGFR gene leading to the formation of EGFRvIII transcript.Aim. To determine structural changes of the EGFR gene (point mutations and amplification of the EGFR gene, EGFRvIII transcript) in tumor samples using different methods and to evaluate their potential clinical significance.Materials and methods. The study included 75 patients with brain gliomas (70 of them glioblastoma) aged 34 to 78 years (mean age 56 years). DNA and RNA isolation was performed from fresh frozen tumor tissue, as well as from peripheral blood leukocytes. EGFR gene mutations were determined by next-generation sequencing (NGS), and β allele frequency (BAF) comparative analysis (normal-tumor) was performed to determine the copy number of chromosome 7 regions. Quantitative polymerase chain reaction was used to confirm the EGFR gene amplification in tumor samples, and reverse transcription-PCR was used to detect EGFRvIII variant.Results. The NGS method revealed 11/70 (16 %) mutations in coding regions of EGFR gene in glioblastoma samples, the EGFR gene amplification was detected in 26/70 (37 %) cases; no structural changes of the EGFR gene were detected in 5 glioma samples (astrocytoma, oligodendroglioma). All cases of EGFR gene amplification detected by NGS were confirmed by quantitative polymerase chain reaction. To search for EGFRvIII transcript, 31 tumor RNA samples were examined, of which EGFR amplification was present in 12 samples. EGFRvIII transcript was detected only in samples with EGFR gene amplification – 4/12 (33 %). To assess the clinical significance of structural gene alterations, the frequency of occurrence in primary and recurrent glioblastoma samples was compared.Conclusion. The NGS method allows to detect both point mutations and amplification of the EGFR gene. The EGFR gene amplification was associated with EGFRvIII mutation in 33 % of cases. No statistically significant differences in the frequency of structural changes in the EGFR gene between primary and relapsed glioblastomas were found.

Introduction. Oncolytic virotherapy is one of the approaches in immunotherapy of solid brain tumors. Measles virus vaccine strains are prospective agents for the therapy of cancers such as neuroblastoma, mesothelioma, and glioblastoma multiforme. The hyperexpression of the CD46 and other receptors on the surface of malignant cells allows the measles virus to infect and lyse the tumor, thus inducing an immune response. However, widespread immunization of the population and the resistance of neoplasms to oncolysis present difficulties in clinical practice.Text. This review covers approaches to modifying the measles virus genome in order to increase specificity of virotherapy, overcome existing immunity, and enhance the oncolytic effect. It was shown that expression of proinflammatory cytokines on viral particles leads to tumor regression in mice and triggers a T-cell response. Several approaches have been used to overcome virus-neutralizing antibodies: shielding viral particles, using host cells, and altering the epitope of the protein that enables entry of the virus into the cell. Furthermore, the insertion of reporter genes allows the infection of target cells to be monitored in vivo. A combination with the latest immunotherapies, such as immune checkpoint inhibitors, demonstrates synergistic effects, which suggests the successful use of combined approaches in the therapy of refractory tumors.Conclusion. Measles virus attenuated strains appear to be an easy-to-modify and reliable platform for the therapy of solid brain tumors.

Background. Clarification of the mechanisms of carcinogenesis induced by foreign bodies is one of the urgent problems of modern oncology. This is due to the fact that there is a relationship between the processes of inflammation and carcinogenesis. Today, there is no doubt the fact that cytokines and signal molecules in the focus of inflammation (products of inflammation) can contribute to the initiation of carcinogenesis, as well as stimulate tumor progression. In the case of carcinogenesis induced by foreign bodies, the key issue is understanding the differences in the body’s response to the implantation of foreign bodies that can cause tumor formation and do not have this ability. One of the phenomena of this type of carcinogenesis is the occurrence of sarcoma after the subcutaneous implantation in mice of hydrophilic millipore filters with a pore diameter not exceeding 0.1 μm and the inability to induce tumors of one’s with a pore diameter greater than or equal to 0.22 μm.The objective of our work was to study the differences between oncogenic and non-oncogenic filters at the molecular level.Materials and methods. Reverse transcription polymerase chain reaction method was used to study the expression of a number of cytokines that are products of macrophage cells that live on the surface of implanted filters and in the surrounding capsule. Filters with pore diameters of 0.025 μm (carcinogenic) and 0.45 μm (non-carcinogenic) were compared in 8, 35 days and 5.5 months after implantation.Results and conclusion. After 8 days we observed significant (p

Objective: to evaluate the possibility of using a highly sensitive method of “enriched” polymerase chain reaction followed by DNA melting analysis (PCR-DMA) for target liquid biopsy of cancer patients.Materials and methods. The “enriched” PCR-DMA was used for mutation scanning of KRAS (codons 12 and 13) in tumor and blood plasma of 20 patients with colorectal cancer.Results. Activated oncogene was found in tumor tissue of 16 patients and in blood plasma of 5 patients (confirmed by sequencing). Mutant KRAS alleles were also found in tumor and plasma of another 2 patients, but in very low concentrations that did not allow their validation by Sanger sequencing. Thus, in our study the target liquid biopsy was successful in ~35 % patients. Since the plasma tests were carried out after repeated medical procedures causing mass death of tumor cells, the actual efficiency of this approach may appear significantly higher.

10 % of genome mRNA expression is rhythmic and these 24-hrs rhythms are under control of the circadian clock. Epidemiologic studies have revealed a clear link between the disruption of circadian rhythms and cancer development in humans. Growing evidence shows that circadian disruption is associated with development of malignant tumors, including breast cancer. Aim of this study was to investigate: the expression of circadian clock genes in human mammary epithelial cell line MCF10A and breast cancer cell lines MCF-7, ZR-75-1, BT-474 and if the multidrug resistance phenotype of cancer cells is associated with changes in circadian clock genes expression. We have found that Per1 expression significantly reduced in cancer cells. No correlation was detected between the expression of circadian clock genes and cancer breast cell lines drug resistance. Interestingly, the expression of Bmal1, Per1 and Cry1 were increased in multi-drug resistant MCF-7_D cells compare with the parent cells MCF-7 cells, however, if these changes in the expression contribute to the drug-resistance or not is not clear. These results argue for further study.