Cancer and Stem Cells

Stem cell therapy is mainly used in cancer treatment so as to allow higher doses of chemotherapy and/or radiation. These cancer treatments kill cancer cells but also damage other cells which have a rapid rate of division, which includes stem cells in the bone marrow. Bone marrow stem cells are responsible for producing blood cells and cells of the immune system and when these are destroyed in chemotherapy and radiation therapy treatments the patient is at risk of infection, along with poor tissue oxygenation and problems with blood clotting. The stem cell transplants offered to patients, using donor bone marrow or peripheral blood stem cells usually, are a way of replacing those healthy stem cells destroyed during cancer treatment.

Stem Cell Transplant for Cancer

There are three types of stem cell transplant for cancer therapy; autologous stem cell transplants where the patient’s own cells are harvested prior to chemotherapy for transplantation afterwards, allogenic stem cell transplant from bone marrow or blood donated by another person, and syngeneic stem cell transplants from an identical twin in rare cases. Identical twins have matching human-leukocyte-associated (HLA) antigens making graft versus host disease (GVHD) much less likely than when another family member or unrelated donor’s blood or tissue is used. The stem cells found in blood and bone marrow and used in most cancer stem cell treatments are haematopoeitic stem cells. These stem cells differentiate into leukocytes (white blood cells) which fight infection, erythrocytes (red blood cells) which carry oxygen around the body, and platelets which help the blood to clot.

Using Stem Cells in Cancer Treatment

Those donating stem cells traditionally had a portion of bone marrow removed which was often painful and exposed the donor to risk of complication themselves. Peripheral blood stem cells are increasingly being used instead of bone marrow for stem cell transplants and are much simpler to harvest and less invasive for the donor. Several drugs have been developed which encourage the stem cells in the bone marrow out into general circulation in order to increase the stem cell yield from apheresis, the technique used to harvest peripheral blood stem cells during donation.

Using stem cells in cancer treatment is far from straightforward however, with a number of researchers now calling for increased scrutiny of stem cells’, particularly mesenchymal stem cells’, capacity for encouraging tumor growth under certain conditions. Far from treating cancer with stem cell therapy, it may be that introducing stem cells into an area where conditions are already favorable for cancer to develop, these stem cells may themselves further contribute to the growth of tumors. It appears that the timing of the introduction of stem cells into the body is a key element of the resulting tumor-promotion or tumor-suppression which is one possible reason for much of the research in this area showing contradictory results (Klopp, et al, 2011). Stem cell treatments previously thought harmless, such as breast augmentation, and stem cell face-lifts could, potentially, create significant problems, although issues do appear to be limited, so far, to mesenchymal stem cells and not specifically haematopoietic stem cells used in cancer treatments themselves.

Read More –> How Stem Cell Treatment Works for Cancer