Microdeletion studies by Paulsen et al. [28] using genome wide array analysis showed involvement of 7p12.2 (IKZF1), 9p21.3 (CDKN2A), 9p13.2 (PAX5), 12p13.2 (ETV6), 13q14 (RB1), 19p13.3 (TCF3) in association with hyperdiploid ALL. This evidence concerns the gene PAX5 and acute lymphoblastic leukemia.