MicroRNA Expression Profiling of High and Low Risk MDS

MicroRNA’s (miR) are small noncoding RNA’s of 18–25 nucleotides that have a critical impact on gene regulation affecting cell growth & differentiation. Importantly, miR expression profiles can help distinguish normal cells from cancerous cells. This is particularly relevant to myelodysplastic syndromes both because of their heterogeneity as well as the difficulties associated with the early diagnosis of these disorders. We investigated the miR profiles of CD34+ and total nucleated cells (TNC) from different subtypes of MDS (n=135) and compared these to AML (n=20), normal CD34+ (n=5) and normal TNC’s (n=6). We used the Illumina universal array matrix to interrogate 470 validated miR’s from the Sanger mir-Base database and a further 265 putative miR’s from the literature. Array intensity data was analysed using the Partek Genomics Suite v6.3. Data was normalised using quantile normalisation and unchanging miR’s removed. A 1-way ANOVA was used to identify differentially expressed miR’s and a FDR correction applied to control for Type I errors. Our initial analysis compared TNC (n=6) with CD34 cells (n=5) from normal controls. As expected both groups clustered separately with mir-199a (p