SET domain proteins are a group of proteins characterized by the presence of a specific SET domain, which is involved in various cellular processes, including gene regulation and chromatin modification. These proteins play crucial roles in the development and maintenance of cellular identity by influencing how genes are expressed. Many SET domain proteins are associated with cancer and other diseases, as mutations or dysregulation can lead to abnormal cell growth and function. They are also involved in epigenetic mechanisms, which help control gene activity without altering the underlying DNA sequence, making them important for understanding cellular biology and potential therapeutic targets.