In summary, abnormalities in any stage of the mitotic cell cycle can lead to chromosomal instability, including increased expression of the CDK1, CCNA2, MKI67, TOP2A, FOXM1, KIF11, CHEK1, BUB1B, and BUB1 genes in T-ALL/T-LBL patients, might be linked with the unfavorable prognosis. This evidence concerns the gene TOP2A and acute lymphoblastic leukemia.