PML-RARA fusion is a genetic alteration commonly associated with a type of cancer called acute promyelocytic leukemia (APL). This fusion occurs when parts of the promyelocytic leukemia (PML) gene and the retinoic acid receptor alpha (RARA) gene combine, leading to the production of an abnormal protein. This protein disrupts normal blood cell development, causing the accumulation of immature white blood cells. The presence of the PML-RARA fusion is a key diagnostic marker for APL and is often detected through genetic testing. Targeted therapies, such as all-trans retinoic acid (ATRA) and arsenic trioxide, have been developed to specifically address this fusion, significantly improving treatment outcomes for patients.