Patients with high BRE expression were confined to a novel subclass in AML. Pairwise correlations of 525 AML patients based on optimal clustering as described before¹⁶  identified several clusters of patients with similar expression profiles which can be recognized by the red blocks showing high correlation along the diagonal. One of these clusters was represented by a high incidence (86%) of patients with high BRE expression; the left 3 black bars show the relative intensity of the 3 probe sets representing BRE expression on the array. The other 3 black bars show the relative expression intensity of the probe set for MRPL33 and 2 probe sets for RBKS as indicated in the figure, revealing coexpression of these chromosomal neighbors with BRE. The MLL-AF9 status of the samples is represented in the green bar (green: negative; red: positive; blue: ND).