NCCN Guidelines for Patients® | Chronic Lymphocytic Leukemia
8 NCCN Guidelines for Patients ® : Chronic Lymphocytic Leukemia, 2019 1 CLL basics A disease of cells progenitor cells. Compared to stem cells, progenitor cells are set to become a certain type of blood cell. Lymphocytes Lymphocytes are a type of white blood cell. They include natural killer cells, B cells, and T cells. Natural killer cells release chemicals that kill diseased cells. B cells make antibodies that mark germs for killing. T cells alert your body that germs are present, kill diseased cells, and help B cells. Lymphocytes form in marrow and are released into the bloodstream. From the bloodstream, they are released into tissue. They return to the bloodstream though the lymphatic system. This system consists of fluid, called lymph, and a network of tissues. Lymph travels in lymph vessels and passes through lymph nodes, which filter out germs and waste. Other organs of the lymphatic system include the thymus, spleen, and tonsils. A disease of cells Your body is made of trillions of cells. Cancer is a disease of cells. Each type of cancer is named after the cell from which it formed. Leukemia Leukemia is a cancer of blood cells. A lot of people call it blood cancer. There are four common types. AML ( a cute m yeloid l eukemia) and ALL ( a cute l ymphoblastic l eukemia) are faster-growing blood cancers. CLL and CML ( c hronic m yeloid l eukemia) are slower-growing blood cancers. CLL vs. SLL CLL and SLL ( s mall l ymphocytic l ymphoma) are thought to be the same cancer. They are both cancers of B cells but differ in where they are found. With CLL, many abnormal B cells are found in the blood. With SLL, there are few, if any, abnormal B cells in the blood. Treatment of these cancers is very similar. Mutations Cells have a control center called the nucleus. The nucleus contains chromosomes, which are long strands of DNA ( d eoxyribo n ucleic a cid) tightly wrapped around proteins. See Figure 2 . Within DNA are coded instructions for building new cells and controlling how cells behave. These instructions are called genes. There can be abnormal changes in genes called mutations. Some types of mutations that are linked to cancer are present in all cells. Other mutations are present only in cancer cells. Mutations cause cancer cells to not behave like normal cells and, sometimes, to look very different from normal cells. Leukemia’s threat CLL is often a slow-growing cancer. But, sometimes it grows fast. If slow growing, you may not know you have CLL for years because you have no symptoms. Over time, CLL results in too many abnormal B cells. The abnormal B cells will crowd out healthy cells in bone marrow. Then, there won’t be enough red blood cells and platelets. As a result, you may feel tired, lose weight, and get sick easily. CLL may also spread to your lymph nodes, liver, and spleen, and cause these organs to enlarge.