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. The gene discussed is BUB1B; the disease is acute lymphoblastic leukemia.