Many of the genes altered in ALL encode proteins with roles in key cellular pathways, including lymphoid development and differentiation (e.g., PAX5, IKZF1, EBF1, LEF1, and VPREB), cell-cycle regulation and tumor suppression [CDKN2A, CDKN2B (INK4/ARF), TP53, PTEN, and RB1], lymphoid signaling (BTLA, CD200, and TOX), transcription factors and transcriptional coregulators (ERG, TBL1XR1, and CREBBP), regulation of apoptosis (BTG1), and drug receptor (NR3C1) (10). This evidence concerns the gene BTLA and acute lymphoblastic leukemia.