What Are Stem Cells?

Stem cell transplants allow doctors to replace the bone marrow stem cells (called hematopoietic stem cells) that give rise to blood cells. These blood cell progenitors give rise to the three types of blood cells:

• Red blood cells
  Red blood cells carry oxygen through your body. A deficiency in red blood cells leads to anemia.
  
  
• White blood cells
  White blood cells are an important part of your immune system. A deficiency in white blood cells can increase your risk of getting a serious infection.
  
  
• Platelets
  Platelets are needed for your blood to clot. A deficiency in platelets can lead to bleeding problems such as heightened bruising and bloody noses and gums.

Blood stem cells that are used for stem cell transplants are different from the kind of stem cells that are used for experimental cloning and the procedures are not related.

When Do Cancer Patients Need a Stem Cell Transplant?

Cancer patients benefit from stem cell transplants when their own blood stem cells have been damaged by either disease or treatment.

Disease-Related Stem Cell Transplant
Many blood cell cancers such as leukemia and lymphoma impair a patient’s stem cells. In these cases a transplant may be part of treatment and may be able to restore normal blood cell function. Because the patient has damaged stem cells, a suitably compatible donor must be found before treatment can begin.

Treatment-Related Stem Cell Transplant
In some cases, doctors may believe a patient with a disease such as breast cancer, renal cancer, Ewing sarcoma, or neuroblastoma may benefit from an extremely high dose of chemotherapy or radiation. A problem with this treatment is that it damages the blood stem cells leaving the patient weak and vulnerable to infections.

Reconstructing a patient’s bone marrow with a stem cell transplant following high-dose treatment makes this therapy significantly safer. In this case, patients have healthy stem cells before treatment so they are able to donate their own stem cells, eliminating the need to find a donor.

Stanford Expertise

The Stanford Blood Center has a large, world-class facility that routinely performs apheresis, a special kind of blood collection that can isolate stem cells from the rest of the blood.

In addition, the center is part of the National Marrow Donor Program (NMDP) Network, which helps patients find stem cell donors if necessary.