Advanced practice nurses (APNs) have received additional education, often at least a master's degree, beyond the courses required for a registered nurse (RN). Advanced practice nurses work in many settings, such as hospitals, clinics, and offices. They may be involved in primary care, preventive care, or research. They may specialize in an area such as cancer care, pediatrics, or geriatrics. Types of APNs include clinical nurse specialists, nurse practitioners, certified nurse midwives (CNMs), and certified registered nurse anesthetists (CRNAs).