Sanitary indicators standardly used in water quality monitoring refer to fecal microorganisms or cyanobacterial toxins, but at present they do not include fungi, despite the fact that many fungi can pose potential health hazards. The aim of study was a quantitative and qualitative assessment of yeast in waters of urban artificial recreational reservoirs in relation to microbiological and sanitary cleanliness indicators and to demonstrate that yeast could be an indicator of anthropogenic pollution. In total, 18 species of yeast were isolated, including 13 classified as clinically relevant. Tested reservoirs exceeded the standards of sanitary indicators acceptable for bathing water. Since isolated yeasts are associated with living organisms, their presence in the water of urban recreational reservoirs may be a public health concern. Therefore, a mycological analysis should be incorporated into standard water quality assessment procedures. The results obtained are very promising, but further research is still needed.

The infectious agents may be the etiological factor of up to 15–20% of cancers. In stomach cancer, attention is paid to Helicobacter pylori and Epstein-Barr virus, both of which cause gastritis and can lead to tumor development. In co-infection, the inflammatory process is much more intense. We assessed the seroprevalence towards H. pylori and EBV in 32 patients with diagnosed gastric cancer. H. pylori antibodies were found in 69% patients, and anti-EBV – in all of them. The study confirmed that co-infection of H. pylori and EBV seems to be important in etiopathology of gastric cancer.

Many types of cancer have infectious origins. Gastric cancer patients can demonstrate high seroprevalence of Helicobacter pylori (H. pylori). The aim of the present study was to assess the expression of SMOX gene in the group of Polish patients with gastric cancer. SMOX is believed to promote H. pylori-induced carcinogenesis via inflammation, DNA damage and activation of β-catenin signaling. We also assessed the mRNA expression of selected pro-inflammatory cytokines, i.e. IL-2, IFN-γ, TNF-α, and antimicrobial peptide, cathelicidin. The study material consisted of gastric tissue samples collected during total gastrectomy from three different places in stomach: from primary tumor, 3cm away from the primary lesion, and from the wall opposite to the primary tumor. After RNA isolation, qPCR reactions were performed for the relevant genes. The obtained results confirmed an increased level of SMOX expression in gastric cancer patients with the history of H. pylori infection. And, as far as we know, this is the first study on SMOX gene expression conducted on tissue taken from a patient, not on a cell line. The levels of pro-inflammatory cytokines, i.e. IL-2, IFN-γ, TNF-α, were also increased, thus indicating their contribution to the specific inflammatory microenvironment of the tumor. Interestingly, the levels of CAMP, encoding antimicrobial peptide, were reduced in all tissue types. The findings confirm that SMOX plays a role in gastric carcinogenesis. However, further research is needed on the role of inflammatory and other factors involved in this process to identify targets for cancer immunotherapy.

It is well established that human body is an ecosystem for numerous microorganisms: bacteria, fungi, eukaryotic parasites, and viruses. They form a “microbiome” that under conditions of homeostasis remains in a friendly mutual relationship with the host. However, the composition and diversity of this microbe community is dynamic and can be changed under the influence of environmental factors, such as diet, antibiotic therapy, lifestyle, and the host’s genotype and immunity. The result of gut microbiome dysbiosis can lead even to cancer. The aim of this review is the description of the healthy gastrointestinal microbiome and the role of two infectious agents: Gram-negative bacteria Helicobacter pylor i and Epstein-Barr virus in the development of gastric cancer in terms of gut dysbiosis. H. pylori is the most important pathogen of gastric microbiome with clear impact on its diversity. Coinfection with Epstein-Barr virus causes chronic gastritis, and the inflammatory process is significantly increased. The process of carcinogenesis begins with chronic inflammation that causes atrophic gastritis, intestinal metaplasia, dysplasia, and finally cancer. It has been proven that chronic inflammatory infection caused by infectious agents increases the risk of stomach cancer. Molecular methods that are progressively used to explore the human microbiome provide hope that this knowledge will be used for future diagnoses and therapy in the state of its dysbiosis and in cases of gastric cancer.

Gastric cancer is often diagnosed late, and is associated with poor long-term prognosis. The aim of the study was to look for non-invasive potential biomarkers involved in gastric carcinogenesis, with diagnostic or prognostic significance. Gastric tissue samples, from three different regions of the stomach, including the primary tumor, macroscopically unchanged gastric tissues, as well as serum, were collected from patients diagnosed with gastric cancer. Serum samples were also obtained from a control group. The analyzed parameters were: expression levels of PTEN, miRNA-21 and miRNA-200a using qPCR method and the frequency of LOH/MSI at the PTEN locus using four microsatellite markers. The obtained results revealed significantly decreased expression of PTEN in gastric tumor tissue and statistically significant differences between the studied tissue samples from different stomach regions. PTEN expression in patients with LOH/MSI was decreased two-fold compared to patients without genetic instability, indicating a potential mechanism of gene silencing. Another mechanism of PTEN silencing could be due to miRNA activity: significant negative correlations were found between PTEN and the studied miRNAs expression levels. In serum, miRNA-21 expression was increased in the group of patients, while miRNA-200a expression was decreased, and the differences were statistically significant compared to controls. Receiver operating characteristic curve analysis for miRNA-200a revealed 92 ​% sensitivity and 77 ​% specificity. The obtained results suggest that miRNA-21 and miRNA-200a could be considered as diagnostic biomarkers differentiating patients with gastric cancer from healthy individuals; however, it should be verified on a larger group of patients.