LEF1-inactivated T-ALL is characterized by the overexpression of MYC and of MYC targets. Gene expression profiling was previously performed on 40 of the 47 T-ALL cases analyzed in our study, using Affymetrix U133 Plus 2.0 microarrays. (A) Heatmap showing the expression pattern of known T-ALL oncogenes, based on the expression microarrays applied. Probe sets that showed no significant expression (defined as expression values < 100) in any T-ALL sample were excluded. Low expression values were truncated to 30. Note that data from the [1561651_s_at] TAL1 probe set were excluded because we have found that expression measured by this probe set does not correlate with TAL1 RNA levels (data not shown). (B-C) Expression of MYC by LEF1 and NOTCH1 status. P values were calculated by the Wilcoxon rank-sum test. (D-F) Gene set enrichment analysis showed that 3 of the 4 gene sets most highly up-regulated in LEF1-inactivated T-ALL represent MYC target gene sets.