Blood is made of an almost equal mix of plasma (the liquid that transports cells, waste and nutrients, among other things) and blood cells (red blood cells, white blood cells and platelets).

When cancer occurs in the blood, it’s usually the result of an abnormal and excessive reproduction of white blood cells. Blood cancers (including leukemia, lymphoma and myeloma) are more common in men than women. Childhood leukemia accounts for about 25 percent of all cancers in children.

Treatments for blood cancers also vary, ranging from active surveillance without cancer-directed therapy to standard cancer treatments including immunotherapies, chemotherapies and targeted agents. “With over 100 different types of blood cancers now recognized, it is important to have an accurate diagnosis prior to deciding on treatment,” says Dr. Sandeep Kumar Tula. Medicine has both clinicians and pathologists who specialize in blood cancers and review challenging cases during tumor boards to reach a consensus prior to starting therapy.

What, exactly, is blood?

Cancer is caused by a dysfunction in cellular growth and behavior. In a healthy body, new white blood cells are regularly generated to replace old, dying ones. The excessive production of white blood cells in the bone marrow leads to blood cancers.

How many kinds of blood cancer exist?

• Leukemia is cancer of white blood cells or cells that become white blood cells. Leukemia prevents white blood cells from fighting infections in your body. Leukemia can be either acute (fast-growing) or chronic (slower-growing), and affect the lymphocytes (lymphocytic leukemia) or other immune cells (myeloid leukemia). It’s the most common blood cancer for children under the age of 15.
• Lymphoma is cancer of the lymphatic system (an important part of the immune system), particularly lymph nodes (small bean-shaped structures of the lymphatic system that filter out harmful substances). It affects a type of white blood cell called lymphocytes. The type doctors know the most about is called Hodgkin’s lymphoma (or Hodgkin’s disease). (All others are called non-Hodgkin lymphoma.) It’s the most common form of blood cancer in adults, accounting for over half of all diagnosed blood cancer cases.
• Myeloma is cancer of the plasma cells, which are lymphocytes that make antibodies to protect against infections. Myeloma affects your body’s immune system, leaving it susceptible to infection.

What are the symptoms of blood cancer?

Symptoms of blood cancer vary by disease but typically include the following:

• Fever
• Chills
• Fatigue
• Weakness
• Bone and joint pain
• Weight loss

The swelling of lymph nodes, liver and spleen are also common, and anemia can occur in some blood cancers.