Identification of genes expressed in CD34⁺ marrow cells that can distinguish between patients with low-risk MDS, those with high-risk MDS, and healthy controls.

(A) Results represent analysis by hierarchical clustering with Spearman confidence correlation of 15 samples of CD34⁺ bone marrow cells (training set). Eleven genes were selected to predict the class membership of each of the samples. Vertical list is each of the samples. Horizontal list displays the 11 genes. (B) Validation of the 11 predictive genes used to distinguish between high-risk and low-risk MDS by gene expression profiling. The 11 predictive genes were used for clustering analysis in a second data set obtained from CD34⁺ cells from patients with low-risk and high-risk MDS (test set). Two clusters corresponding to the IPSS classifications high-risk and low-risk were found. No misclassification of any of the samples of the test set occurred, demonstrating the power of the selected genes for risk group prediction. One high-risk sample, however, was classified in a separate subcluster (sample 3883). Blue indicates low expression; red, high expression. Intensity of the color reflects the reliability of the expression data.