NANOG is an important stem cell transcription factor involved in human development and cancerogenesis. Its expression is complex and regulated on different levels. Moreover, NANOG protein might regulate hundreds of target genes at the same time. NANOG is crucial for preimplantation development phase and progressively decreases during embryonic stem cells differentiation, thus regulating embryonic and fetal development. Postnatally, NANOG is undetectable or expressed in very low amounts in the majority of human tissues. NANOG re-expression can be detected during cancerogenesis, already in precancerous lesions, with increasing levels of NANOG in high grade dysplasia. NANOG is believed to enable cancer cells to obtain stem-cell like properties, which are believed to be the source of expanding growth, tumor maintenance, metastasis formation, and tumor relapse. High NANOG expression in cancer is frequently associated with advanced stage, poor differentiation, worse overall survival, and resistance to treatment, and is therefore a promising prognostic and predictive marker. We summarize the current knowledge on the role of NANOG in cancerogenesis and development, including our own experience. We provide a critical overview of NANOG as a prognostic and diagnostic factor, including problems regarding its regulation and detection. Impact statement NANOG has emerged as a key stem cell transcription factor in normal development and cancerogenesis. It is generally regarded as a good prognostic and predictive factor in various human cancers. It is less known that it is expressed already at precancerous stages in various organs, suggesting that finally an ideal candidate diagnostic marker has been discovered, enabling to distinguish between true dysplasia and reactive atypia. NANOG regulation is complex, and new insights into our understanding of its regulation might provide important information for future development in a broad field of two entirely different processes, i.e. normal development and cancerogenesis, showing how a physiologic mechanism can be used and abused, transforming itself into a key mechanism of disease development and progression.

Slovenia is a very diverse country from a natural geography point of view, with many different habitats within a relatively small area, in addition to major geological and climatic differences. It is therefore not surprising that several small mammal species have been confirmed to harbour hantaviruses: A. flavicollis (Dobrava virus), A. agrarius (Dobrava virus–Kurkino), M. glareolus (Puumala virus), S. areanus (Seewis virus), M. agrestis, M. arvalis and M. subterraneus (Tula virus). Three of the viruses, namely the Dobrava, Dobrava–Kurkino and Puumala viruses, cause disease in humans, with significant differences in the severity of symptoms. Due to changes in haemorrhagic fever with renal syndrome cases (HFRS) epidemiology, a detailed study on phylogenetic diversity and molecular epidemiology of pathogenic and non-pathogenic hantaviruses circulating in ecologically diverse endemic regions was performed. The study presents one of the largest collections of hantavirus L, M and S sequences obtained from hosts and patients within a single country. Several genetic lineages were determined for each hantavirus species, with higher diversity among non-pathogenic compared to pathogenic viruses. For pathogenic hantaviruses, a significant geographic clustering of human- and rodent-derived sequences was confirmed. Several geographic and ecological factors were recognized as influencing and limiting the formation of endemic areas.

Background. Results of previous studies suggest that NANOG may be an important prognostic biomarker in oral squamous cell carcinoma (OSCC), but there are contradictory results regarding NANOG expression patterns on mRNA and protein levels, and the mechanisms of its regulation are poorly understood. Our aim was to analyze the expression and diagnostic significance of NANOG in OSCC, and the possible mechanisms of its regulation, i.e., protein regulators on mRNA level (OCT4, SOX2, KLF4, AGR2, and NOTCH1), methylation status, copy number variation, and regulatory miRNAs, miR-145, miR-335, miR-150, miR-34a, miR-128, and miR-27a. Methods. Our study included 120 patients with OSCC. Expression of NANOG protein and mRNA was analyzed using immunohistochemistry and qPCR. Expression of regulatory factors, miRNAs, and copy number variation was performed using qPCR. Methylation status of NANOG promoter was determined using PCR and Sanger sequencing. Results. We detected upregulation of NANOG and OCT4 and downregulation of NOTCH1 and AGR2 mRNA in OSCC with lymph node metastases compared to OSCC without lymph node metastases. We observed a strong positive correlation between mRNAs of NANOG and those of its protein regulators OCT4, SOX2, NOTCH1, AGR2, and KLF4. The expression of NANOG was in positive correlation with the expression of miR-34a. There was also a correlation between T status of OSCC and the expression of miR-335 and miR-150 and a correlation of miR-150 with the N status of T2 OSCC. NANOG promoter methylation and copy number variation were only observed in a small proportion of samples. Conclusions. Our findings confirm the diagnostic significance of NANOG in OSCC and provide information on NANOG expression patterns on both mRNA and protein levels. They also suggest that protein regulators and microRNAs might play a crucial role, whereas methylation of its promoter and copy number variation probably have a minor role in the regulation of NANOG expression in OSCC.

Background: Different cytology preparations can be used for molecular diagnostics, however the influence of pre-analytical and analytical steps on the results are not yet well defined. We aimed to determine optimal steps for efficient extraction of DNA and RNA from fresh cells for molecular diagnostics.Methods: MCF7 and FaDu human cell lines, were used as a model to determine fresh cells storage conditions (temperature: 25°C, 4°C, −20°C, −80°C; duration: 0 h, 4 h, 12 h, 24 h, 48 h) and optimal nucleic acids extraction method. Besides, the minimal number of total cells and minimal percentage of mutated cells needed for successful extraction of nucleic acids and subsequent determination of present mutation were evaluated.Results: Extraction of nucleic acids using spin columns yielded the highest quantity and quality of nucleic acids. Isolation of nucleic acids was feasible in all storage conditions, however higher temperature and longer duration of fresh cells storage were associated with lower quality of isolated nucleic acids and similar quantification cycle of housekeeping genes. Successful molecular testing was feasible with least 10 4 cells, while specific mutation was detected in as low as 5% of mutated cells. Conclusions:Our cell line model, mimicking fresh cytology samples, showed that quantity of extracted either DNA or RNA declined with higher temperatures and longer duration of storage but regardless of the storage conditions, we successfully detected both housekeeping genes and mutated gene using qPCR.

Aims IgA vasculitis (IgAV) is a common small‐vessel systemic vasculitisthat is histologically characterised by granulocyte infiltration and IgA deposition in vessel walls. Information on microRNA (miRNA) involvement inIgAVis limited. The aim of this study was to analyse the association between histopathological changes and expression profiles of 14 miRNAs in the affected skin of 70 adult patients with IgAV. Methods and results miRNA expression analysis was performed by quantitative real‐time polymerase chain reaction and evaluation of histopathological changes by light and immunofluorescence microscopy on formalin‐fixed paraffin‐embedded skin excision samples. In IgAV‐affected skin, granulocyte infiltration was significantly associated with vessel fibrinoid necrosis. Of the analysed miRNAs, four showed two‐fold increased expression (let‐7d, let‐7f, miR‐21‐5p, and miR‐203‐3p), five showed five‐fold increased expression (let‐7b, miR‐17‐5p, miR‐155‐5p, miR‐423‐5p, and miR‐451a), and threeshowed 15‐fold increased expression (let‐7a, miR‐21‐3p, miR‐223‐3p), as compared with controls (all P < 0.001). miR‐146a‐5p and miR‐148b‐3p showed three‐fold decreased expression (P = 0.981 and P < 0.001). The expression of miR‐223‐3p also showed a significant positive association with granulocyte infiltration and fibrinoid necrosis. Conclusions Altered miRNA expression, especially of miRNA‐223‐3p, may be associated with the skin inflammatory state in IgAV. The majority of aberrantly expressed miRNAs in IgAV‐affected skin are known to influence the nuclear factor‐κB signalling pathway, which is crucial for activation of key proinflammatory genes, including those encoding tumour necrosis factor‐α, interleukin (IL)‐6, and IL‐8. Furthermore, miR‐146a‐5p and miR‐148b‐3p, which are negative regulators of inflammatory gene expression, showed decreased expression and could contribute to the exaggerated inflammation. Further investigation of miRNA expression in the affected tissues could improve our knowledge of IgAV pathogenesis, and possibly help to identify novel biomarkers in body fluids.