Immunotherapy is a type of cancer treatment. It uses substances made by the body or in a laboratory to boost the immune system and help the body find and destroy cancer cells.

A bone marrow transplant is a medical treatment that replaces your bone marrow with healthy bone marrow stem cells. It is also called a stem cell transplant or, more specifically, a hematopoietic stem cell transplant. This type of transplantation can treat certain types of cancer and other diseases that affect the bone marrow. Like any cancer treatment, it can cause side effects. These side effects can be different for everyone and depend on the type of transplant you receive, your general health, and other factors.

During cancer care, doctors may collect a sample of a patient's bone marrow to see how well these cells develop and work. This testing is called a bone marrow aspiration or a bone marrow biopsy. It can be done to diagnose some types of cancer, learn more about a diagnosis, or monitor cancer treatment.

Bone marrow is the spongy, fatty tissue inside your body's larger bones. It has liquid and solid parts.

Bone marrow makes these types of blood cells:

• Red blood cells carry oxygen to all parts of the body.

Cancer.Net Specialty Editor: Childhood Cancers
Cancer Therapy Evaluation Program (CTEP).
National Cancer Institute, Bethesda, MD

Dr. Nita L. Seibel is an adjunct professor of pediatrics at George Washington University School of Medicine and Public Health and practices at Children’s National Medical Center.