The Ras gene product is a monomeric membrane-localized G protein of 21 kd that functions as a molecular switch linking receptor and nonreceptor tyrosine kinase activation to downstream cytoplasmic or nuclear events. Each mammalian cell contains at least three distinct ras proto-oncogenes encoding closely related, but distinct proteins. Activating mutations in these Ras proteins result in constitutive signaling, thereby stimulating cell proliferation and inhibiting apoptosis. Oncogenic mutations in the ras gene are present in approximately 30% of all human cancers. K-ras mutations occur frequently in non-small-cell lung, colorectal, and pancreatic carcinomas; H-ras mutations are common in bladder, kidney, and thyroid carcinomas; N-ras mutations are found in melanoma, hepatocellular carcinoma, and hematologic malignancies. The ras-signaling pathway has attracted considerable attention as a target for anticancer therapy because of its important role in carcinogenesis. In this review, the physiologic and biochemical properties of the Ras proteins, their mechanism of cell signaling, and their relation to human cancer will be discussed. Novel cancer therapeutic approaches based on the inhibition of Ras-mediated signaling, including inhibition of Ras processing, inhibition of Ras protein synthesis, and blockage of downstream Ras effectors, will be discussed.

Blocking oncogenic Ras signaling for cancer therapy.

Human alteration of the nitrogen cycle has resulted in steadily accumulating nitrate in our water resources. The U.S. maximum contaminant level and World Health Organization guidelines for nitrate in drinking water were promulgated to protect infants from developing methemoglobinemia, an acute condition. Some scientists have recently suggested that the regulatory limit for nitrate is overly conservative; however, they have not thoroughly considered chronic health outcomes. In August 2004, a symposium on drinking-water nitrate and health was held at the International Society for Environmental Epidemiology meeting to evaluate nitrate exposures and associated health effects in relation to the current regulatory limit. The contribution of drinking-water nitrate toward endogenous formation of N-nitroso compounds was evaluated with a focus toward identifying subpopulations with increased rates of nitrosation. Adverse health effects may be the result of a complex interaction of the amount of nitrate ingested, the concomitant ingestion of nitrosation cofactors and precursors, and specific medical conditions that increase nitrosation. Workshop participants concluded that more experimental studies are needed and that a particularly fruitful approach may be to conduct epidemiologic studies among susceptible subgroups with increased endogenous nitrosation. The few epidemiologic studies that have evaluated intake of nitrosation precursors and/or nitrosation inhibitors have observed elevated risks for colon cancer and neural tube defects associated with drinking-water nitrate concentrations below the regulatory limit. The role of drinking-water nitrate exposure as a risk factor for specific cancers, reproductive outcomes, and other chronic health effects must be studied more thoroughly before changes to the regulatory level for nitrate in drinking water can be considered.

Workgroup report: Drinking-water nitrate and health--recent findings and research needs.

https://zenodo.org/record/1009492/files/StrategiesforaddressingvaccinehesitancyAsystematicreview.pdf

Strategies for addressing vaccine hesitancy – A systematic review☆

MicroRNAs (miRNAs) are endogenous ∼23 nt RNAs that play important gene-regulatory roles in animals and plants by pairing to the mRNAs of protein-coding genes to direct their posttranscriptional repression. This review outlines the current understanding of miRNA target recognition in animals and discusses the widespread impact of miRNAs on both the expression and evolution of protein-coding genes.

MicroRNAs: Target Recognition and Regulatory Functions

https://cyberleninka.org/article/n/244203.pdf

Measuring vaccine hesitancy: The development of a survey tool

The carcinogenic feature of N-nitroso compounds has been well established. Similarly, the transformation of ingested nitrate to N-nitroso compounds in the stomach has been thoroughly documented, nevertheless nitrates' carcinogenic effect has not been proved convincingly in human. The present study was aimed to investigate a population of small villages provided by drinking water with high and widely variable nitrate content (72 mg/l median, 290.7 mg/l 95-percentile concentration). Empirical Bayes estimates for settlement-specific age-, sex-, and year-standardised mortality ratios of gastric cancer (GC) were related to the settlement level average nitrate concentrations in drinking water controlling for confounding effects of smoking, ethnicity and education. The log-transformed average nitrate concentration showed significant positive association with stomach cancer mortality in linear regression analysis (p = 0.014). The settlements were aggregated according to the nitrate concentration into 10-percentile groups and the standardised mortality ratios (SMRs) were calculated. Those groups with higher than 88 mg/l average nitrate concentration showed substantial risk elevation and the log-transformed exposure variables proved to be significant predictors of mortality (p equals; 0.032) at this level of aggregation also. The association seemed to be fairly strong (r2 equals; 0.46). Although this investigation constituting an ecological study has certain limitations, it supports the hypothesis that the high level of nitrate in drinking water is involved in the development of GC.

Association between gastric cancer mortality and nitrate content of drinking water: Ecological study on small area inequalities

Adolescents' awareness of HPV infections and attitudes towards HPV vaccination 3 years following the introduction of the HPV vaccine in Hungary.

Effect of an educational intervention on Hungarian adolescents' awareness, beliefs and attitudes on the prevention of cervical cancer.

Background/Aim: The role of oncogenic or high- risk human papillomavirus (HPV) in cervical carcinogenesis is inevitable, yet not fully understood. Detailed analysis of microRNA (miRNA) alterations occurring during high-risk HPV transformation will increase our current understanding over cervical carcinogenesis. The two main aims of the study were: (i) finding association between HPV infection characteristics and socio-demographic variables, (ii) finding an predictors of clinical outcome. Materials and Methods: The expression levels of different microRNAs (miR-21, miR- 27a, miR-34a, miR-155, miR-196a, miR-203) were determined in formalin-fixed paraffin-embedded (FFPE) human HPV-positive cervical dysplastic and tumorous tissue samples using quantitative real-time PCR (qPCR). Sociodemographic and life-style factors were also analyzed. Results: The expression of miR-27a was significantly higher in cervical intraepithelial neoplasia (CIN)2-3 compared to CIN1 (p=0.023) and in squamous cell carcinoma (SCC) compared to CIN2-3 (p=0.033). Moreover, significantly lower levels of miR-34a were detected in CIN2-3 than in CIN1 (p=0.041) and in SCC than in CIN2-3 (p=0.021). Furthermore, we found significant differences in subjects with multiple HPV in miR-27a (p=0.015) and miR-203 (p=0.025) in CIN2-3 compared to CIN1 and miR-21 (p=0.002), mir-27a (p=0.001) and miR-34a (p=0.001) in SCC/CIN2-3. Expression of miR-27a, showing up-regulation in CIN2-3 compared to CIN1 (p=0.028) and miR-34a (down- regulated), correlated with HPV 16 positivity (CIN2-3/CIN1: p=0.027 and SCC/CIN2-3: p=0.036). MiR-34a expression was also significantly altered in connection to smoking status and presence of HPV 16. Conclusion: The demand for additional, alternative molecular biomarkers with prognostic potential is strong. Evaluation of miRNA expression might be helpful to distinguish different cervical lesions and might be able to help in the prediction of HPV infection outcome. Based on the latest worldwide cancer statistics, cervical cancer is the third most commonly diagnosed cancer in females with

MicroRNA expressions in HPV-induced cervical dysplasia and cancer.

Background: Cancer of the colorectal region is the second most frequent cause of death among malignant diseases. The influence of two allelic polymorphisms of GSTM1 and GSTT1, and that of p53 gene codon 72 on colon cancer was investigated. Patients and Methods: Intraoperatively removed tissue samples were processed from colorectal cancer patients. Cancer-free human samples were used as matched controls. Samples were digested with proteinase-K. DNA solution was used for PCR amplification. Results: No significant difference was found between tumor patients and controls in the investigated polymorphisms. A significant association was found in Dukes' B stage patients between the GSTM1 and p53 gene variants and survival. In patients with GSTM1 null genotype and p53 Arg/Pro heterozygotes or Pro/Pro homozygotes the chance of survival is significantly lower than in the case of GSTM1+ and p53 Arg/Arg variants (p=0.009 and p=0.008, respectively). Conclusion: The significance of the investigated polymorphisms in prognosis is dependent on the tumor stage. These parameters might be used in certain cases as prognostic biomarkers in clinical diagnostics and in the planning of individual therapy. Malignancies of the gastrointestinal tract are among the most frequent malignant diseases in Hungary (1). Cancer of the colorectal region is the second most frequent cause of death from malignant diseases (2). Traditional gastronomical habits which include fatty and dietary fiber deficient foods and the popularity of meats preserved by smoke explain the high prevalence of these diseases (3). In our present study we aim to examine the relationship between certain allelic polymorphisms and related cancer risk, and its influence on the survival of inflected patients. Our area of interest is in two allelic polymorphisms of glutathione-S-transferases, the GSTM1 and GSTT1 metabolizing enzymes. Glutathione-S-transferases (GSTs) are involved in the metabolism of endogenous and exogenous carcinogenic substances, such as environmental carcinogens, reactive oxygen species and chemotherapeutic

István Kiss

Papers

Association between gastric cancer mortality and nitrate content of drinking water: Ecological study on small area inequalities

Adolescents' awareness of HPV infections and attitudes towards HPV vaccination 3 years following the introduction of the HPV vaccine in Hungary.

Effect of an educational intervention on Hungarian adolescents' awareness, beliefs and attitudes on the prevention of cervical cancer.

MicroRNA expressions in HPV-induced cervical dysplasia and cancer.

GSTM, GSTT and p53 polymorphisms as modifiers of clinical outcome in colorectal cancer.