['Managing aggressive breast cancers with enhanced chromosomal instability (CIN) is a significant challenge in clinics. Previously, we described that a cell cycle-associated kinase called Tousled-like kinase 2 (TLK2) is frequently deregulated by genomic amplifications in aggressive estrogen receptor-positive (ER'] Does amplification of TLK2 induce Genomic Instability via Impairing the G2-M Checkpoint?