243 research outputs found

    The Role of miRNAs and lncRNAs in Laryngeal Squamous Cell Carcinoma - a Mini-Review

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    Laryngeal squamous cell carcinoma is a common malignancy in men. Bulgaria is one of the countries in Europe with the highest incidence and mortality rates of the aggressive, severe disease of laryngeal cancer. Proven etiological factors are the abuse of tobacco and alcohol beverages. Despite the progress of technologies of multimodal medical treatment, survival rates have not reached satisfactory levels. Over the last few decades, scientific and clinical research data have led to a growing interest in exploring potential biomarkers. In the last years, non-coding RNAs have become promising biomarkers. They are important key regulators in both normal and tumour specific biological processes as well as in the response to environmental factors and treatment, including chemo- and radiotherapy. Studies have shown ectopic expression of a number of ncRNAs in laryngeal cancer. Published data provide evidence of the lncRNAs and miRNAs that could help us better understand complex carcinogenesis in laryngeal cancer and would provide reliable diagnostic, prognostic and predictive biomarkers

    A pilot study reveals the potential of miR-31-3p and miR-196a-5p as non-invasive biomarkers in advanced laryngeal cancer

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    Introduction: Recently, miRNAs have become popular molecules used as non-invasive biomarkers in cancer diseases.Aim: The aim of the study was to explore the expression of four miRNAs isoforms: miR-31-3p, miR-196a-5p, miR-210-3p and miR-424-5p in plasma and tissue samples from patients with advanced laryngeal squamous cell carcinoma (LSCC) and healthy controls.Materials and methods: Fresh-frozen tumour and normal laryngeal tissue as well as plasma samples were obtained from 22 patients diagnosed with advanced LSCC. The control group included plasma samples from 21 cancer-free volunteers. Total RNA (including miRNAs) extraction, reverse transcription and real time qPCR were the laboratory techniques used in the study. The obtained results were analyzed using SPSS software v. 23.Results: We found that miR-31-3p, miR-196a-5p, and miR-210-3p levels were significantly elevated in laryngeal tumour tissue, but only the levels of miR-31-3p and miR-196a-5p were significantly upregulated in the plasma LSCC target group. Positive correlation was obtained for miR-31-3p (rs=0.443, p=0.039) and miR-196a-5p (rs=0.548; p=0.008) between plasma and adjacent tumour tissue LSCC samples. ROC analyses were used to evaluate the discriminative power of both miRNAs alone and in combination. The combination of miR-31-3p and miR-196a-5p showed best results with AUC=0.978 (95% CI: 0.945–1.000, p<0.001) with 100% sensitivity and 81% specificity at cut-off: RQ=2.99.Conclusions: Based on this miR-31-3p and miR-196a-5p are proposed as potential biomarkers for validation in larger LSCC group and could be included in a non-invasive miRNAs set for detection of advanced LSCC

    Detection of different colistin resistance mechanisms among multidrug resistant Klebsiella pneumoniae isolates in Bulgaria

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    The more frequent usage of colistin resulted in an increase of colistin resistance due to lipopolysaccharide modifications. The aim of this study was to reveal the prevalence and mechanisms of colistin resistance among multidrug-resistant Klebsiella pneumoniae isolates collected in Bulgaria. One hundred multidrug resistant K. pneumoniae isolates were collected in a period between 2017 and 2018. Among them, 29 colistin resistant and 8 heteroresistant isolates were observed and further investigated. Clonal relatedness was detected by RAPD and MLST. Carbapenemases, two component system phoQ/phoP, pmrA/B, and mgrB were investigated by PCR amplification and Sanger sequencing. Among 37 colistin nonsusceptible isolates, we detected 25 NDM-1 producers. The isolates belonged mainly to ST11 (80%), and also to ST147, ST35, ST340, ST219 (1-2 members per clone). Nine colistin resistant isolates showed changes in mgrB. IS903B-like elements truncated mgrB in five isolates. In two isolates, premature stopcodon (Q30stopcodon) was observed and another two isolates did not amplify mgrB, possibly due to bigger deletion or insertion. No isolates showed phoQ/phoP and pmrA/B mutations except for pmrB (four isolates had R256G). All isolates with IS903B insertions belonged to ST11 clone. The mgrB alterations play major role in colistin resistance in K. pneumoniae isolates studied in the current work. We report truncation of mgrB by IS903 like element in colistin resistant NDM-1 producing K. pneumoniae ST11 clone in Bulgaria
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