Primary central nervous system lymphoma (PCNSL) is a rare, highly aggressive, extranodal form of non-Hodgkin lymphoma, predominantly diagnosed as primary diffuse large B-cell lymphoma of the central nervous system (CNS DLBCL). Fast and precise diagnosis of PCNSL is critical yet challenging. microRNAs, important regulators in physiology and pathology are potential biomarkers. In 131 patients with CNS DLBCL and with non-malignant brain lesions (n-ML), miR-21, miR-19b and miR-92a, miR-155, miR-196b, miR-let-7b, miR-125b, and miR-9 were examined by RT-qPCR in brain biopsy samples (formalin-fixed paraffin-embedded tissues, FFPET; CNS DLBCL, n = 52; n-ML, n = 42) and cerebrospinal fluid samples (CSF; CNS DLBCL, n = 30; n-ML, n = 23) taken for routine diagnosis. FFPET samples were split into study and validation sets. Significantly higher CSF levels of miR-21, miR-19b, and miR-92a were identified in PCNSL but not in n-ML, and differentiated PCNSL from n-ML with 63.33% sensitivity and 80.77% specificity. In FFPETs, miR-155 and miR-196b were significantly overexpressed and miR-let-7b, miR-125b, and miR-9 were downregulated in PCNSL as compared to n-ML. Combined miR-155 and miR-let-7b expression levels in FFPETs discriminated PCNSL and n-ML with a 97% accuracy. In conclusion, tissue miR-155, miR-196b, miR-9, miR-125b, and miR-let-7b expression profiles differentiate PCNSL from n-ML. PCNSL CSFs and the relevant biopsy samples are characterized by specific, different microRNA profiles. A logistic regression model is proposed to discriminate between PCNSL and non-malignant brain lesions. None of the examined microRNAs influenced overall survival of PCNSL patients. Further ongoing developments involve next generation sequencing-based profiling of biopsy and CSF samples.

Background: Non-small cell lung cancer (NSCLC) accounts for 80% of lung cancers, the leading cause of cancer mortality. microRNAs (miRNA, miR) have emerged as important components of carcinogenesis and promising biomarkers. We aimed to analyse global plasma miRs in NSCLC patients before and at least one year after tumour resection. Methods: Plasma was collected from the peripheral blood of 24 donors without cancer and of NSCLC patients before surgery (n=36) and at least 1 year after surgery (n=12). Next-generation sequencing (NGS)-based miR profiling was performed. Patients were followed-up for 4 to 12 years after surgery to assess disease recurrence. Results: Untreated NSCLC patients exhibited significant changes in plasma miR levels compared to cancer-free donors (48 up- and 17 down-regulated miRs). miR profiles in patients with adenocarcinoma (ADC) (n=18) and squamous cell carcinoma (SCC) significantly differed (16 and 86 miRs up-, and 15 and 16 miRs down-regulated, respectively). A subset of pre-surgery deregulated miRs was found to be associated with recurrence (49 miRs). Six miRs were shown to have independent prognostic value. After tumour resection, some pre-surgery miR alterations returned to control levels (18 miRs), some others persisted (27 miRs), while also novel plasma miR changes emerged (75 miRs) in patients with no clinical evidence of recurrence. Conclusions: Untreated NSCLC patients present deregulated plasma miRs, some of which may have a potential of prognostic markers. After tumour excision plasma miR profiles change, some miR levels normalise, some changes persist and novel miR changes are observed despite no clinical symptoms of recurrence. Plasma miR profiles in NSCLC patients may suggest systemic abnormalities predisposing to lung cancer and/or reflect a systemic response to pre-cancer/dormant cancer cells.

High-grade B-cell lymphoma with 11q aberration (HGBCL-11q) is a rare germi-nal centre lymphoma characterised by a typical gain/loss pattern on chromo-some 11q but without MYC translocation. It shares some features with Burkitt lymphoma (BL), HGBCLs and germinal centre-derived diffuse large B-cell lym-phoma, not otherwise specified (GCB-DLBCL-NOS). Since microRNA expression in HGBCL-11q remains unknown, we aimed to identify and compare the mi-croRNA expression profiles in HGBCL-11q, BL and in GCB-DLBCL-NOS. Next-generation sequencing (NGS)-based microRNA profiling of HGBCL-11q (n = 6), BL (n = 8), and GCB-DLBCL-NOS without (n = 3) and with MYC rearrange-ment (MYC-R) (n = 7) was performed. We identified sets of 39, 64, and 49 mi-croRNAs differentiating HGBCL-11q from BL, and from GCB-DLBCL-NOS without MYC-R, respectively. The expression levels of miR-223-3p, miR-193b-3p, miR-29b-3p, and miR-146a-5p consistently differentiated HGBCL-11q from both BL, GCB-DLBCL-NOS without MYC-R. In addition, HGBCL-11q presented greater heterogeneity in microRNA expression than BL. The expression profile of MYC-regulated microRNAs differed in HGBCL-11q and in BL, while also clearly distinguishing HGBCL-11q and BL from GCB-DLBCL-NOS. The microRNA pro-file of HGBCL-11q differs from those of BL and GCB-DLBCL-NOS, exhibiting greater heterogeneity compared to BL. The microRNA profile further supports that HGBCL-11q is a distinct subtype of B-cell lymphoma.