Small nucleolar RNAs as new biomarkers in chronic lymphocytic leukemia. Homo sapiens

Small nucleolar RNAs (snoRNAs) and small Cajal body-specific RNAs are non-coding RNAs involved in the maturation of other RNA molecules. Alterations of sno/scaRNA expression may play a role in cancerogenesis. This study elucidates the patterns of sno/scaRNA expression in highly purified cells from 211 chronic lymphocytic leukemia (CLL) patients (Binet stage A) also in comparison with those of different normal B-cell subsets. CLLs display a sno/scaRNAs expression profile similar to normal memory, naïve and marginal-zone B-cells, with the exception of a few down-regulated transcripts (SNORA31, -6, -62, and -71C). Our analyses also suggest some heterogeneity in the pattern of sno/scaRNAs expression which is apparently unrelated to the major biological (ZAP-70 and CD38), molecular (IGHV mutation) and cytogenetic markers. Moreover, we found that SNORA70F was significantly down-regulated in poor prognostic subgroups and this phenomenon was associated with the down-regulation of its host gene COBLL1. Finally, we generated an independent model based on SNORA74A and SNORD116-18 expression, which appears to distinguish two different prognostic CLL groups. These data extend the view of sno/scaRNAs deregulation in cancer and may contribute to discover novel biomarkers associated with the disease and potentially useful to predict the clinical outcome of early stage CLL patients. Overall design: This series of microarray experiments contains the gene expression profiles of purified B-cell chronic lymphocytic leukemia (B-CLL) cells obtained from 211 patients (Binet stage A), 6 normal controls from peripheral blood mononuclear cells (BC), and B-cell sub-populations from tonsils (3 naïve B-cells (N), 2 marginal zone (MZ)-like, 3 switched memory (SM) B-cells and 4 germinal center (GC) ). For gene and miRNA expression profiling experiments CLL cells were enriched by negative selection with the EasySep-Human B cell enrichment kit without CD43 depletion (Stem Cell Technologies) using the fully automated protocol of immunomagnetic cell separation with RoboSepTM (Stem Cell Technologies).