STAT5B and acute lymphoblastic leukemia: To further elucidate whether STAT5 is directly involved in TCR pathway gene regulation, we performed ChIP-Seq analysis for STAT5B in 4 T-ALL cell lines with high pY-STAT5 levels (KOPT-K1, DND-41, HSB-2, and SUP-T13) and 2 with low pY-STAT5 levels (LOUCY and JURKAT; Figure 5A).