LEF1 and acute lymphoblastic leukemia: This study also confirmed the deletions of PAX5 (9p13), EBF (5q33), IKAROS (7p12.2), AIOLOS (17q12), LEF1 (4q25), RAG1 (11p12), and RAG2 (11p12) in pediatric ALL, albeit with a lower frequency except PAX5. Uniparental disomy (UPD) was frequently identified, especially in chromosome 9.