Thursday, October 28, 2010
A few days ago we talked about how blood cancer research is important for understanding other cancers as well. To help all of that make sense, today I’ll go through the basics of blood cancer.
Cancer is characterized by the uncontrolled growth of cells. Although they have this growth characteristic in common, different types of cancer, such as lung cancer, breast cancer, and skin cancer, are actually separate diseases. To make things even more complex, blood cancer is itself comprised of several different diseases.
Blood cancers are characterized by the uncontrolled growth of cells in the bone marrow and lymphatic system, often called white blood cells. Let’s start at the beginning. All blood cells originate in the bone marrow. They develop along very particular paths into two major lineages called myeloid cells and lymphoid cells.
Both myeloid and lymphoid cells are part of the immune system. Myeloid cells, like granulocytes, fight disease-causing agents non-specifically. In contrast, lymphoid cells, B- and T-cells, are immune cells that each recognize a specific substance as foreign.
Any of these cell types can be involved in cancer if they are induced to grow uncontrollably (for instance, by mutations in the DNA). Leukemia, lymphoma and myeloma are the most common blood cancers, distinguished by the origin and type of cell involved.
Leukemia originates in the bone marrow and can involve either myeloid or lymphoid cells.
In contrast, lymphomas originate in the lymphatic tissue, particularly the lymph nodes. In addition, lymphomas are lymphoid in origin, involving B- or T-cells. Unlike leukemia, where the cancer cells circulate in the blood, lymphomas actually form a solid tumor.
Myeloma, like leukemia, originates in the bone marrow, but it involves a very particular cell called a plasma cell, which comes from a B-cell, a lymphoid cell.
This table might help to keep it all straight:
By studying and understanding normal blood development, researchers can better understand what is occurring in cancer. And, as we saw a couple days ago, understanding blood cancer can lead to breakthroughs in other cancers as well. The beauty of research is you never know what you're going to learn, which just illustrates the importance of supporting all types of research.