All-trans Retinoic Acid (ATRA) is a metabolite of Vitamin A that plays a crucial role in cellular growth and differentiation. It is commonly used in dermatology for treating skin conditions like acne and psoriasis, as it helps to promote cell turnover and reduce inflammation. In addition to its dermatological applications, ATRA is also significant in the field of oncology. It is used in the treatment of certain types of leukemia, particularly Acute Promyelocytic Leukemia (APL), where it helps to induce remission by promoting the differentiation of cancerous cells.