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MicroRNAs (miRNAs) are small non coding RNAs responsible for posttranscriptional regulation of gene expression. Even though almost 2000 precursors have been described so far, additional miRNAs are still being discovered in normal as well as malignant cells. Alike protein coding genes, miRNAs may acquire oncogenic properties in consequence of altered expression or presence of gain or loss of function mutations. In this study we mined datasets from miRNA expression profiling (miRNA-seq) of 7 classic Hodgkin Lymphoma (cHL) cell lines, 10 non-Hodgkin lymphoma (NHL) cell lines and 56 samples of germinal center derived B-cell lymphomas. Our aim was to discover potential novel cHL oncomiRs not reported in miRBase (release 22.1) and expressed in cHL cell lines but no other B-cell lymphomas. We identified six such miRNA candidates in cHL cell lines and verified the expression of two of them encoded at chr2:212678788-212678849 and chr5:168090507-168090561 (GRCh38). Interestingly, we showed that one of the validated miRNAs (located in an intron of the TENM2 gene) is expressed together with its host gene. TENM2 is characterized by hypomethylation and open chromatin around its TSS in cHL cell lines in contrast to NHL cell lines and germinal centre B-cells respectively. It indicates an epigenetic mechanism responsible for aberrant expression of both, the TENM2 gene and the novel miRNA in cHL cell lines. Despite the GO analysis performed with the input of the in silico predicted novel miRNA target genes did not reveal ontologies typically associated with cHL pathogenesis, it pointed to several interesting candidates involved in i.e. lymphopoiesis. These include the lymphoma related BCL11A gene, the IKZF2 gene involved in lymphocyte development or the transcription initiator GTF2H1.

Laryngeal squamous cell carcinoma (LSCC) is the most common group among head and neck cancers. LSCC is characterized by a high incidence in Europe. With the aim of better understanding its genetic background we performed global miRNA expression profiling of LSCC cell lines and primary specimens. By this approach we identified a cohort of 33 upregulated and 9 downregulated miRNA genes in LSCC as compared to epithelial no tumor controls.Within this group we identified overexpression of the novel miR-1290 gene not reported in the context of LSCC before. Using a combined bioinformatical approach in connection with functional analysis we delineated two putative target genes of miR-1290 namely ITPR2 and MAF which are significantly downregulated in LSCC. They are interesting candidates for tumor suppressor genes as they are implicated in apoptosis and other processes deregulated in cancer.Taken together, we propose miR-1290 as the new oncomiR involved in LSCC pathogenesis. Additionally, we suggest that the oncogenic potential of miR-1290 might be expressed by the involvement in downregulation of its target genes MAF and ITPR2.