This study aimed to investigate the anticancer potential of three tetracycline analogues chemically modified tetracycline-3 (COL-3), doxycycline (DOX), and minocycline (MIN) in leukemia models, with a particular focus on their cytotoxic effects and modulation of the JAK2/STAT3 signaling pathway. The gene discussed is STAT3; the disease is leukemia.