Эпигенетика-наука об обратимых наследственных изменениях функционирования гена, которые происходят без изменений в нуклеотидной последовательности ДНК. Один из важнейших маркеров нарушений эпигенетической регуляции генома клеткиасинхронность репликации ДНК биаллельно экспрессирующихся генов. Удобным методом оценки нарушения синхронности репликации (асинхронной репликации) в культивированных лимфоцитах периферической крови человека, как правило, является интерфазная флуоресцентная in situ гибридизация (I-FISH). В обзоре проведен анализ работ, направленных на изучение асинхронной репликации биаллельно экспрессирующихся генов в лимфоцитах периферической крови онкологических больных. Этот анализ показал, что асинхронная репликация-неспецифический маркер злокачественных новообразований и наблюдается как у онкогематологических больных, так и у пациентов с солидными опухолями, причем не только в клетках опухоли, но и в лимфоцитах периферической крови. Проведенный анализ продемонстрировал, что встречаемость лимфоцитов с асинхронной репликацией изученных генов у онкологических больных достоверно повышена по сравнению со здоровыми лицами и увеличивается в процессе малигнизации (злокачественного перерождения) заболеваний. Это дает потенциальную возможность использовать асинхронную репликацию как молекулярно-генетический маркер для раннего выявления лиц с онкологическими заболеваниями.

The aim of the study was to identify and quantify lymphocytes with asynchronous replication of the AURKA and TP53 genes in cancer patients versus controls and to assess the diagnostic capabilities of this approach.Materials and Methods. The study was carried out with peripheral blood lymphocytes probed for the AURKA and TP53 genes using the interphase fluorescence in situ hybridization (FISH) method (Vysis, USA and Kreatech, The Netherlands). The control group included 70 people: clinically healthy donors and patients with non-oncological diseases such as gastritis, pancreatitis, chronic calculous cholecystitis, bronchial asthma, peptic ulcer disease, inguinal hernia, arthrosis, myoma, hepatitis, epilepsy, chronic prostatitis, chronic tonsillitis, and rectal adenoma. The group of cancer patients included 219 people with various oncological diseases: gastric cancer (n=68), colorectal cancer (n=30), chronic lymphocytic leukemia (n=52), Hodgkin lymphoma (n=33), and polyneoplasia (n=41).Results. In the control group, the mean frequency of lymphocytes with asynchronous gene replication (AGR) was 22.0±3.4% for AURKA and 18.0±3.2% for TP53; in the group of cancer patients, that was 36.8±4.8 and 28.4±5.1%, respectively. The excessive presence of lymphocytes with the AGR in cancer patients was consistent and statistically significant (p<0.0001). For the AURKA gene, the AGRbased cancer detection showed a sensitivity of 98.6±0.7%, a specificity of 100%, and an accuracy of 98.3±0.8%, and for the TP53 gene -78.6±3.1, 98.5±0.9, and 85.9±2.6%, respectively.Conclusion. This pilot study on lymphocytes with AGR of AURKA and TP53 genes in cancer patients can serve a basis for creating a new molecular cytogenetic technology for detecting malignant neoplasms in humans.

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Background. The correct genome replication is essential for normal cell division to guarantee that genetic information comes changeless through the next cells generations. DNA replication is a strictly regulated and synchronous process and its disturbances could result to mutations appearances. Aberrant time of DNA replication affects on gene expression causes changes of epigenetic modifications and influences on increasing the structural rearrangements leading to enhanced genome disbalance. Replication time failure as asynchronous replication is common for cancerogeneses. The objective of our study was the assessment of asynchronous replication levels in patients with gastric cancer and patients with multiple tumors.Materials and methods. Fluorescence in situ hybridization (FISH) was used for the asynchronous replication of AURKA and TP53 genes analyses. Interphase FISH on lymphocytes of peripheral blood of 37 healthy donors, 19 patients with non-cancer gastrointestinal pathologies, 68 patients with solitary gastric cancer and 39 patients with multiple tumors having gastric cancer and other second synchronous or metachronous tumor was carried out.Results. Values of lymphocytes with asynchronous replication for AURKA were 19.8 ± 0.5 % for control group, 24.7 ± 0.4 % for non-cancer patients, 32.5 ± 0.5 % for gastric cancer patients, 39.5 ± 0.6 % for patients with multiple tumors and 17.3 ± 0.5, 19.5 ± 0.7, 26.1 ± 0.7 and 32.5 ± 0.6 % for TP53 respectively. Differences between cell populations of examined groups had statistical significance with p <0.01 for both studied gene. Also there was statistical difference between gastric cancer patients having distant metastases and gastric cancer patients without metastases for AURKA (34.4 ± 1.0 % vs. 31.7 ± 0.6 %; p = 0.02).Conclusion. High lymphocytes with asynchronous replication level in oncological patients could serve as potential marker of second tumor or possible metastatic process including the earliest stage of it.