Hedgehog components are ectopically expressed in a subgroup of T-ALL patients. (A) Heat map showing the relative expression of genes encoding hedgehog components in a cohort of 88 T-ALL patients. Patients were ordered based on the expression of the 9 hedgehog pathway genes. (B) GLI1 expression levels correlate with expression of the hedgehog ligands SHH and IHH. (C) The hedgehog pathway signature is enriched in T-ALL patients with high GLI1 levels. Patients were categorized in “High,” “Intermediate,” or “Low” based on the expression levels of the GLI1 gene. Subsequent GSEA between “High” and “Low” patients identified hedgehog pathway as significantly upregulated. (D) Correlation between expression levels of GLI1 and known GLI1 target genes. A significant correlation was found with PTCH2, CCND1, and BCL2, but not with PTCH1. (E) Box plots showing the relative expression of 6 genes of the hedgehog pathway during normal mouse T-cell development and in T-ALL patients with high or low GLI1 expression. *P < .05; **P < .01; ***P < .001. Error bars indicate SEM.