Blood Cancer Awareness Month

Leukemia

Leukemia is the name given to a group of cancers that develop in the bone marrow. Under normal conditions the bone marrow contains a small number of healthy immature blood cells, sometimes called blast cells. These immature blood cells mature and develop into red cells, white cells, and platelets, which are eventually released into the blood stream.

Leukemia originates in developing blood cells, which have undergone a malignant (cancerous) change. Instead of maturing properly, these cells grow and multiply in an uncontrolled fashion and interfere with normal blood cell production in the bone marrow. Most cases of leukemia originate in developing white cells. In a small number of cases leukemia develops in other blood-forming cells, for example in developing red cells or developing platelets.

There are several different types and subtypes of leukemia.

Acute/chronic Leukemia and Blood Cancer Awareness Month

• Leukemia can be either acute or chronic. The terms ‘acute’ and ‘chronic’ refer to how quickly the disease develops and progresses. Acute leukemia develops and progresses quickly and therefore needs to be treated as soon as it is diagnosed. It affects very immature blood cells, preventing them from maturing properly.
• Chronic leukemia results in an accumulation of more mature but abnormal white cells. It can occur at any age, but is more common in older adults and is rarely seen in children.

Myeloid/lymphoid and Blood Cancer Awareness Month

Leukemia can also be either myeloid or lymphoid. The terms myeloid and lymphoid refer to the types of cell lineage in which the leukemia first started. When leukemia starts somewhere in the myeloid cell line, it is called myeloid (myelocytic, myelogenous or granulocytic) leukemia. When leukemia starts somewhere in the lymphoid cell line it is called lymphoblastic, lymphocytic, or lymphatic leukemia.

The four main types of leukaemia are:

• Acute lymphoblastic leukemia (ALL)
• Chronic lymphocytic leukemia (CLL)
• Acute myeloid leukemia (AML)
• Chronic myeloid leukemia (CML)

Both adults and children can develop leukemia but certain types are more common in different age groups.

Lymphoma

Lymphoma is the general term for cancers that develop in the lymphatic system. This originates in developing B-lymphocytes and T-lymphocytes, which have undergone a malignant (cancerous) change. This means that they multiply without any proper order forming tumors, which are collections of cancer cells. These tumors cause swelling in the lymph nodes and other parts of the body. Over time, malignant lymphocytes (called lymphoma cells) crowd out normal lymphocytes and eventually the immune system becomes weakened and can no longer function properly.

• The World Health Organization currently recognizes over 40 different subtypes of lymphoma with five of these sub-types belonging to a group of diseases called Hodgkin lymphoma. All other sub-types are commonly grouped together and called Non-Hodgkin lymphomas (or B- and T-cell lymphomas).
• Non-Hodgkin lymphoma is seen in all age groups, but is more common in people over the age of 50. In children, non-hodgkin lymphoma and leukemia (bone marrow cancer) are the most common types of cancer seen, but few children overall are ever diagnosed with these diseases. Lymphomas in children tend to grow quickly and they are often curable.
• Significant advances are continually being made in the way we manage lymphomas. This means that with treatment, many people can now be cured. Many others who are treated remain disease-free and well for a long time.

Myeloma

• Myeloma, also known as multiple myeloma or plasma cell myeloma, is a cancer of plasma cells (mature B-lymphocytes) that usually arises in the bone marrow.
• Myeloma develops when plasma cells undergo a malignant (cancerous) change and become myeloma cells. These myeloma cells multiply without any proper order, forming collections known as tumors that accumulate in different parts of the body, most commonly in the bone marrow and on the surfaces of different bones in the body.
• Myeloma cells secrete chemicals that stimulate other bone marrow cells (osteoclasts) to remove calcium from the bone. As a result bones can become weaker, more brittle and break more easily.
• Under normal conditions, plasma cells produce immunoglobulins (antibodies) that help protect the body from infection and disease. Myeloma cells produce an abnormal type of immunoglobulin called a paraprotein (also known as monoclonal immunoglobulin, myeloma protein, or simply M protein). This can be detected in the blood.
• As myeloma cells multiply, they crowd the bone marrow and prevent it from making normal numbers of red cells, white cells, and platelets. Myeloma cells can also interfere with the production of normal antibodies.
• This can make people with myeloma anaemic, more susceptible to infections and to bleeding and bruising more easily. Excess immunoglobulin fragments can also cause damage to the kidneys.
• The myeloma type is described by which type of excess immunoglobulin is produced. Each immunoglobulin is made up of a combination of two ‘heavy’ chains and two ‘light’ chains. If excess heavy chains are produced it is termed heavy chain myeloma, and if excess light chains are produced it is called light chain myeloma.