РАК ЖЕЛУДКА: СОВРЕМЕННЫЕ МОЛЕКУЛЯРНО-ГЕНЕТИЧЕСКИЕ ДАННЫЕ (ОБЗОР ЛИТЕРАТУРЫ)

In the review a data about molecular and genetic aspects of different morphological variants of gastric cancer in population and family studies are generalized. Data about multiple genetic and epigenetic damages in oncogenes, tumor suppressor genes, cell cycle regulators, adhesion molecules, DNA repair genes as well as genetic instability and telomerase activation involved in the multistep process of carcinogenesis and making a contribution to uncontrolled growth and ability to form metastases are included in the review. In article possibilities of use of specific molecular markers for early GC diagnostics are discussed.Обобщены современные данные о молекулярно-генетических поломках, выявленных при разных морфологических вариантах рака желудка в популяционных и семейных исследованиях. Приводятся сведения о множественных генетических и эпигенетических поломках в онкогенах, генах-супрессорах опухолей, регуляторах клеточного цикла, адгезивных молекулах, генах репарации ДНК, а также генетической нестабильности и активации теломераз, вовлеченных в многоступенчатый процесс канцерогенеза и вносящих вклад в скорость опухолевого роста и метастазирования. Обсуждаются возможности использования специфических молекулярных маркеров для ранней диагностики рака желудка и прогноза выживаемости

ПОЛИМОРФИЗМ ГЕНА ТР53 У ПАЦИЕНТОВ С РАКОМ ЖЕЛУДКА В ПОПУЛЯЦИОННОМ ПРОСПЕКТИВНОМ И КЛИНИЧЕСКОМ ИССЛЕДОВАНИЯХ

Background. A functionally significant TP53Arg72Pro polymorphism can contribute to the development of gastric cancer (GC).The aim: to study the associations of genotypes and alleles of the TP53Arg72Pro 4 polymorphism with GC and biomarkers of gastric ucosal atrophy in population-based prospective and case-control clinical trials among the population of Siberia.Material and methods. As a part of the epidemiological study, data of the international multicenter HAPIEE project for 2003–05, based on a population sample of residents of Novosibirsk city (serum and  DNA samples) and data of the population-based registry of GC  (2012) were compared. Gastric cancer patients were matched by  age and sex to HAPIEE population controls. A total of 156 serum  samples (GC – 52, control – 104) and 146 DNA samples (GC – 50,  control – 96) were available for prospective analysis. DNA samples  from 80 gastric cancer patients (45 men and 35 women, mean age  61.0 ± 13.4 years) and from 87 age-and sex-matched controls were  analyzed. DNA samples from venous blood were genotyped  according to standard methods. Serum samples were tested using  diagnostic kit for enzyme-linked immunosorbent assays to determine the levels of pepsinogen I (PGI), PGII, PGI/PGII ratio, gastrin-17 and IgG antibodies to H. pylori.Results. No differences in genotype and allele frequencies of the TP53 gene between the case group and the control group were  found. A decreased frequency of the Pro allele in female gastric  cancer patients compared with controls indicated that the Pro allele  is protective against the development of gastric cancer, but this  effect was not observed in male patients. No associations of TP53  genotypes with the risk of diffuse or intestinal gastric cancer, as well  as with the age and sex of patients were found. A high frequency of  genotypes with the Pro allele in patients with stage III–IV gastric  cancer indicated the relationship between Arg/Pro TR53 and tumor  progression, in particular, the contribution of the minor Pro allele to  the unfavorable prognosis. A prospective study showed high risk of  reducing the level of pepsinogen for assessing predisposition to  gastric cancer.Conclusion. Two case-control studies (population and clinical) conducted in the Western Siberia found no relationship between the  TP53Arg72Pro polymorphism and the risk of gastric cancer. However, the TP53 genotype with a rare Pro allele was associated with atrophic gastritis and severity of gastric cancer.Актуальность. Функционально значимый полиморфизм Arg72Pro 4 экзона гена онкосупрессора ТР53 может вносить вклад в развитие рака желудка (РЖ).Цель исследования – изучить ассоциации генотипов и аллелей полиморфизма Arg72Pro 4  экзона гена ТР53 с РЖ и биомаркерами атрофии слизистой у пациентов с РЖ в популяционном проспективном и клиническом исследованиях «случай-контроль» в сибирской популяции.Материал и методы. В рамках эпидемиологического исследования были сопоставлены  база международного многоцентрового проекта HAPIEE, сформированная в 2003–05 гг. на  популяционной выборке жителей Новосибирска (образцы ДНК и сыворотки крови хранились при –70 ºС), и данные популяционного регистра РЖ (2012 г). Для каждого случая РЖ в  соотношении 1:2 был подобран соответствующий по возрасту и полу контроль из базы  HAPIEE. 156 образцов сыворотки крови (РЖ – 52, контроль – 104) и 146 образцов ДНК (РЖ – 50, контроль – 96) оказались доступны для проспективного анализа. В клинической группе  проанализирована серия случаев РЖ (45 мужчин и 35 женщин, средний возраст – 61,0 ±  13,4 годы) из 2 специализированных лечебных учреждений. В качестве «контроля» из базы  HAPIEE были использованы образцы ДНК 87 человек, подобранных к «случаям» по полу и  возрасту. Образцы ДНК из венозной крови генотипировали по стандартным методикам.  Образцы сыворотки тестировали с помощью диагностикумов для иммуноферментного анализа с определением уровней пепсиногена I (ПГI), ПГII,  соотношения ПГI/ПГII, гастрина-17 и IgG антител к H. рylori.Результаты. Частоты генотипов и аллелей гена ТР53 у пациентов с РЖ в обоих исследованиях не различались, как и между группами «случай» и «контроль».  Снижение частоты аллеля Pro у женщин с РЖ по сравнению с контролем дает основания  рассматривать Pro аллель в качестве защитного в отношении формирования рака желудка.  Для мужчин такой закономерности не отмечено. Не обнаружено связи генотипов ТР53 с  риском развития диффузного или интестинального типов рака желудка, а также ассоциаций  с возрастом и полом пациентов. Высокая частота генотипов с аллелем Pro у больных РЖ III– IV стадии свидетельствует о возможном влиянии генетического статуса ТР53 по Arg/Pro полиморфизму на опухолевую прогрессию, в частности, вклад минорного аллеля Pro в  неблагоприятный прогноз. В проспективном исследовании получены данные о высокой  рисковой значимости снижения уровня пепсиногена для оценки предрасположенности к раку желудка.Выводы. В двух исследованиях «случай-контроль» (популяционном и клиническом) в  регионе Западной Сибири не найдено связи полиморфизма Arg72Pro гена ТР53 с риском  развития рака желудка. Однако генотип ТР53 с редким аллелем Pro ассоциирован с  атрофическим гастритом, который является предраковым состоянием, а также c клиническим течением РЖ

Идентификация маркеров аденокарциномы желудка на основе биоинформатического поиска и анализа генной экспрессии

Introduction. Searching for specific and sensitive molecular tumor markers is one of the important tasks of modern oncology. These markers can be used for early tumor diagnosis and prognosis as well as for prediction of therapeutic response, estimation of tumor volume or to assess disease recurrence through monitoring. Gene expression data base mining followed by experimental validation of results obtained is one of the promising approaches for searching of that kind.Objective: to identify several membrane proteins which can be used for serum diagnosis of intestinal type of gastric adenocarcinoma.Materials and methods. We used bioinformatic-driven search using Gene Ontology and The Cancer Genome Atlas (TCGA) data to identify mRNA up-regulated in gastric cancer (GC). Then, the expression levels of the mRNAs in 55 pare clinical specimens were investigated using reverse transcription polymerase chain reaction.Results. Comparative analysis of the mRNA levels in normal and tumor tissues using a new bioinformatics algorithm allowed to identify 3 high-copy transcripts (SULF1, PMEPA1 and SPARC), intracellular content of which markedly increased in GC. Expression analysis of these genes in clinical specimens showed significantly higher mRNA levels of PMEPA1 and SPARC in tumor as compared to normal gastric tissue. Interestingly more than twofold increase in expression level of these genes was observed in 75 % of intestinal-type GC. The same results were found only in 25 and 38 % of diffuse-type GC respectively.Conclusions. As a result of original bioinforamtic analysis using TCGA data base two genes (PMEPA1 and SPARC) were shown to be significantly upregulated in intestinal-type gastric adenocarcinoma. The findings show the importance of further investigation to clarify the clinical value of their expression level in stomach tumors as well as their role in carcinogenesis.Введение. Одна из важных задач современной онкологии – поиск ассоциированных с опухолями молекулярных маркеров, которые могут использоваться для диагностики и прогнозирования рака, оценки степени радикальности операции и последующего лечения, а также раннего выявления рецидивов. Одним из продуктивных вариантов подобного поиска является анализ транскриптомных баз данных с применением методов биоинформатики с последующей валидацией полученных результатов на клиническом материале.Цель исследования – поиск мембранных белков, которые могут быть использованы для сывороточной диагностики аденокарциномы желудка интестинального гистологического типа.Материалы и методы. Идентификацию потенциальных маркеров рака желудка (РЖ) проводили с использованием баз данных Gene Ontology и the Cancer Genome Atlas (TCGA). Последующую оценку дифференциальной экспрессии генов выполняли на парных образцах аденокарциномы и нормальной ткани желудка, взятых от 55 пациентов. Экспрессию генов оценивали с помощью полимеразной цепной реакции с обратной транскрипцией в режиме реального времени по методу ΔCq.Результаты. Сравнительный анализ уровней синтеза матричных РНК (мРНК) нормальных и опухолевых тканей с применением нового алгоритма биоинформатического поиска привел к идентификации 3 наиболее высококопийных транскриптов (SULF1, PMEPA1 и SPARC), внутриклеточное содержание которых заметно повышается при РЖ. При анализе уровня мРНК данных генов в клиническом материале наблюдалось более чем двукратное увеличение уровня экспрессии PMEPA1 и SPARC в 75 % образцов РЖ интестинального гистологического типа. В образцах РЖ диффузного гистологического типа этот показатель составил 25 и 38 % соответственно.Выводы. Использование оригинального биоинформатического подхода, основанного на анализе данных TCGA, позволило выявить 2 гена (PMEPA1 и SPARC), преимущественно экспрессирующихся в опухолях желудка интестинального типа. Полученные результаты свидетельствуют об актуальности дальнейшего исследования роли этих генов в патогенезе РЖ и оценки клинической значимости уровня их экспрессии в опухолевой ткани

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Gastric cancer (GC) remains one of the most important gastrointestinal cancers worldwide. The incidence and mortality rate from GC in Russia is higher in comparison with other European countries and USA. It should be noted that riskometry for the GC doesn’t exist. Parallel assessment of pepsinogen I (PG I), pepsinogen II (PG II), PG I/PG II ratio and gastrin-17 (G-17), as well as antibodies to Helicobacter pylori is an exact and validated set of stomach-specific biomarkers that reflect the extent and grade of gastric atrophy as a main premalignant condition for GC. Aim: To study the diagnostic and predicting value of biomarkers of atrophic gastritis (AG) in retro-prospective cohort case-control study in Siberian population. Object and methods: General population sample was surveyed in Novosibirsk in 2003–2005 (10.000 subjects aged 45–69 years). Each serum sample was deeply frozen and stored. In 2008 and 2012 this database was compared with the data of the Population Cancer Registry. As a result of cross-sectional analysis of two databases 60 novel cases of GC were identified until 2011. For each case of GC, an appropriate control case was selected at the ratio 1:2 matching the area of residence, sex and age. Finally, 156 serum samples (52 – GC group and 104 – control group) were available for the analysis using a panel of serum biomarkers “Gastropanel” (Biohit, Finland). Criteria for “Gastropanel” in the diagnosis of AG were used: PG I <30μg/l, PG II <3μg/l, the ratio PG I/PG II <3, the level of basal G-17<1 pmol/l, and the presence of antibodies to H. pylori. Results: Mean level of biomarkers did not differ between those with, and without GC, with the exception for PG I/PGII ratio, which was significantly lower in GC group. Indicators of gastric atrophy (OR; 95% CI) were associated with GC for PG I (2.9; 1.3–6.4), PG II (9.0; 1.8–44.3), and PG I/PG II (3.3; 1.5–7.3), but neither for G-17 (0.7, 0.4–1.6), nor for the presence of antibodies to H. pylori (0.4; 0.1–1.3). Multivariate regression analysis including sex, age of the patients, all biomarkers of “Gastropanel” confirmed PG I and PGI/PGII ratio as the most powerful indicators in the model. Atrophy Index (AI) was calculated as a sum of abnormal parameters of gastric atrophy (PG I, PG I/PG II ratio and G-17, see Table, ∗p < 0.019; ∗∗p < 0.006). AI 3 (all biomarkers below normal range) was more common in GC patients than in controls. Groups Severity of atrophy (Atrophy Index score) (%) 3 2 1 0 Gastric cancer 14.0∗∗ 20.0 10.0 56.0 Control 2.2 10.8 11.8 75.3∗ Conclusion: As a first step in the development of GC riskometry was found that noninvasive set of serological biomarkers is an informative and non-expensive tool for the early detection of GC in population-based retrospective cohort survey in Siberian population. Low levels of PGI and PGI/PGII ratio were proven as the most valuable prognostic factors. The low level of G-17 as a single index did not significantly predict the risk of GC

Dose-dependent esomeprasole antisecretory effect: results of long-term intragastric pH monitoring

Aim of investigation. To study antisecretory activity of the first dose of esomeprazole (20 or 40 mg) (Emanera®, «KRKA», Slovenia) by long-term intragastric pH monitoring. Material and methods. Long-term intragastric pH monitoring was carried out in 20 patients with acidrelated diseases by «Gastroskan-24» device («IstokSistema», Fryazino, Russia). In the first 24 hours patients received no antisecretory agents, in the morning of the next day - they received esomeprazole 20 or 40 mg orally 30 min. prior to the breakfast. Median pH, both time with various pH values and area under pH distribution curve, percent of this time with values from 1,0 to 10,0 per day before and after esomeprazole administration were estimated. The respective scores were compared, using Wilcoxon criterion. Differences were considered to be significant at

GASTRIC CANCER: MOLECULAR AND GENETIC DATA (LITERATURE REVIEW)

In the review a data about molecular and genetic aspects of different morphological variants of gastric cancer in population and family studies are generalized. Data about multiple genetic and epigenetic damages in oncogenes, tumor suppressor genes, cell cycle regulators, adhesion molecules, DNA repair genes as well as genetic instability and telomerase activation involved in the multistep process of carcinogenesis and making a contribution to uncontrolled growth and ability to form metastases are included in the review. In article possibilities of use of specific molecular markers for early GC diagnostics are discussed

Biomarkers of gastric atrophy at stomach cancer

Background. Atrophic gastritis (AG), being the basic premalignant condition for the stomach cancer (SC), is commonly diagnosed and screened for by noninvasive biomarkers (pepsinogens, gastrin-17), however the data on those biomarkers at SC is inconsistent. Aim of investigation. To evaluate the markers of stomach atrophy along with risk factors of SC of different localization, histological type and stage in the «case series» study. Material and methods. Original investigation was designed as «case series», that included 85 patients with SC (48 m and 37 f, mean age 61.2±13,6 years) who were consistently referred to two medical institutions. All patients underwent interviewing the questionnaire concerning smoking and alcohol consumption, presence of gastroenterological symptoms and family history. Blood serum samples were analyzed using ELISA test kits «GastroPanel» («Biohit Plc», Finland). Manufacturer recommended threshold levels were used at diagnostics of AG. Results. The diagnosis of SC of the III to IV stage was established in 67.9% of patients. The most common location of the neoplasm was the stomach body (63,5%). Helicobacter pylori (H. pylori) infection was revealed by serological method in 74.1% of cases, of which in 15.1% the attempt of eradication treatment was carried out. In 90.6% of patients the adenocarcinoma of different differentiation grade was diagnosed, low degree of differentiation was the most common (57.6%). Signet-ring cell carcinoma was diagnosed in 7.1% of patients, undifferentiated tumor - in 2.4%. Pepsinogen-I (PGI) level under 50 mcg/l was found in 43.2% of patients, indicating different degrees of fundic atrophy. Significantly lower PGI scores were detected in SC patients with histologically verified atrophy. No significant differences in biomarker levels according to tumor location, histological type of SC and tumor stage were found. Conclusions. The «case series» study demonstrated high rate of late SC diagnostics with predominance of corpus location and the most malignant types. H. pylori infection was diagnosed in serologically in the most of patients, however attempts for eradication therapy was carried out only in 15% of patients. Fundic atrophy was diagnosed by serological tests in over 40% of patients, however no association with location, stage and morphological type of the tumor was established. Blood serum samples were analyzed using ELISA test kits «GastroPanel» («Biohit Plc», Finland). Manufacturer recommended threshold levels were used at diagnostics of AG