Theodoros Loupis

Ribonucleotide Reductase (RNR) is a two-subunit (RRM1, RRM2) enzyme, responsible for the conversion of ribonucleotides to deoxyribonucleotides required for DNA replication. To evaluate RNR as a biomarker of response to 5-azacytidine, we measured RNR mRNA levels by a quantitative real-time PCR in bone marrow samples of 98 patients with myelodysplastic syndrome (MDS) treated with 5-azacytidine with parallel quantification of the gene promoter’s methylation. Patients with low RRM1 levels had a high RRM1 methylation status (p = 0.005) and a better response to treatment with 5-azacytidine (p = 0.019). A next-generation sequencing for genes of interest in MDS was also carried out in a subset of 61 samples. Splicing factor mutations were correlated with lower RRM1 mRNA levels (p = 0.044). Our results suggest that the expression of RNR is correlated with clinical outcomes, thus its expression could be used as a prognostic factor for response to 5-azacytidine and a possible therapeutic target in MDS.

Background and Objectives Somatic mutations in the calreticulin gene (CALR) are detected in approximately 70% of patients with essential thrombocythemia (ET) and primary or secondary myelofibosis (MF), lacking the JAK2and MPLmutations. To determine the prevalence of CALRframeshift mutations in a population of MPN patients of Greek origin, we developed a rapid low-budget PCR-based assay and screened samples from 5 tertiary Haematology units. This is a first of its kind report of the Greek patient population that also disclosed novel CALRmutants. Methods MPN patient samples were collected from different clinical units and screened for JAK2and MPLmutations after informed consent was obtained. Negative samples were analyzed for the presence of CALRmutations. To this end, we developed a modified post Real Time PCR High Resolution Melting Curve analysis (HRM-A) protocol. Samples were subsequently confirmed by Sanger sequencing. Results Using this protocol we screened 173 MPN, JAK2and MPLmutation negative, patients of Greek origin, of whom 117 (67.63%) displayed a CALRexon 9 mutation. More specifically, mutations were detected in 90 out of 130 (69.23%) essential thrombocythaemia cases (ET), in 18 out of 33 (54.55%) primary myelofibrosis patients (pMF) and in 9 out of 10 (90%) cases of myelofibrosis secondary to ET (post-ET sMF). False positive results were not detected. The limit of detection (LoD) of our protocol was 2%. Furthermore, our study reavealed 6 rare novel mutations which are to be added in the COSMIC database. Conclusions Overall, our method could rapidly and cost-effectively detect the mutation status in a representative cohort of Greek patients; the mutation make-up in our group was not different from what has been published for other national groups.

Salivary gland tumors (SGTs) comprise a rare and heterogenous category of benign/malignant neoplasms with progressively increasing knowledge of the molecular mechanisms underpinning their pathogenesis, poor prognosis, and therapeutic treatment efficacy. Emerging data are pointing toward an interplay of genetic and epigenetic factors contributing to their heterogeneity and diverse clinical phenotypes. Post-translational histone modifications such as histone acetylation/deacetylation have been shown to actively participate in the pathobiology of SGTs, further suggesting that histone deacetylating factors (HDACs), selective or pan-HDAC inhibitors (HDACis), might present effective treatment options for these neoplasms. Herein, we describe the molecular and epigenetic mechanisms underlying the pathology of the different types of SGTs, focusing on histone acetylation/deacetylation effects on gene expression as well as the progress of HDACis in SGT therapy and the current status of relevant clinical trials.

The strain that dominated in Greece during the first pandemic wave was primarily imported from a group of returning travelers in February 2020, while molecular and clinical data suggest that the origin of the transmission was Egypt. The observed molecular transmission clusters reflect the transmission dynamics of this particular strain bearing the D614G mutation while highlighting the necessity of their use as a surveillance tool for the prioritization of nonpharmaceutical interventions and combating present and future outbreaks.

Background Omicron-1 COVID-19 is less invasive in the general population than previous viral variants. However, clinical course and outcome of hospitalised patients with SARS-CoV-2 pneumonia during the shift of the predominance from Delta to Omicron variants are not fully explored.Methods During January 2022 consecutively hospitalised patients with SARS-CoV-2 pneumonia were analysed. SARS-CoV-2 variants were identified by a 2-step pre-screening protocol and randomly confirmed by whole genome sequencing analysis. Clinical, laboratory and treatment data split by type of variant were analysed along with logistic regression of factors associated to mortality.Results 150 patients [mean age (SD) 67.2(15.8) years, male 54%] were analysed. Compared to Delta (n = 46), Omicron-1 patients (n = 104) were older [mean age (SD): 69.5(15.4) vs 61.9(15.8) years, p = 0.007], with more comorbidities (89.4% vs 65.2%, p = 0.001), less obesity (BMI >30Kg/m2 in 24% vs 43.5%, p = 0.034) but higher vaccination rates for COVID-19 (52.9% vs 8.7%, p < 0.001). Severe pneumonia (48.7%), pulmonary embolism (4.7%), need for invasive mechanical ventilation (8%), administration of dexamethasone (76%) and 60-day mortality (22.6%) did not significantly differ. Severe SARS-CoV-2 pneumonia independently predicted mortality [OR 8.297 (CI95% 2.080–33.095), p = 0.003]. Remdesivir administration (n = 135) was protective from death both in unadjusted and adjusted models [OR 0.157 (CI95% 0.026-0.945), p = 0.043.Conclusions In a COVID-19 department the severity of pneumonia that did not differ between Omicron-1 and Delta variants predicted mortality whilst remdesivir remained protective in all analyses. Death rates did not differ between SARS-CoV-2 variants. Vigilance and consistency with prevention and treatment guidelines for COVID-19 is mandatory regardless of the predominant SARS-CoV-2 variant