Canine Leukemia Types

Canine leukemia can involve the bone marrow, or the lymph nodes. In the majority of veterinarian-documented cases of canine leukemia, dogs are more likely to develop canine leukemia that affects the lymph nodes. There are four main categories that canine leukemia will fall into, each with several subcategories.

Acute Lymphoid Leukemia (also called ALL)

Acute lymphoid leukemia is defined as a situation in which over 30% of the white blood cells present in a dog's bone marrow are deemed cancerous. This is usually a serious condition, as dogs with acute canine leukemia may only live several days or weeks, depending on how fast the cancer is progressing. Specific subcategories under this type of leukemia include:

• Precursor B Acute Lymphoid Leukemia
• Precursor T Acute Lymphoid Leukemia
• Acute Biphenotypic Leukemia

Acute Myeloid Leukemia (also called AML)

This type of leukemia is a cancer that affects the myeloid blood cells. This leads to a growth of abnormal white blood cells, which then interfere with the specific production of new, healthy red blood cells. This type of leukemia causes adverse effects on a dog’s health as the healthy bone marrow cells are replaced with cancerous cells. As this occurs, a subsequent drop in red blood cells, platelets (the cells that aid in blood clotting) and non-cancerous white blood cells is initiated.

Chronic Lymphoid Leukemia (also called CLL)

Chronic lymphoid leukemia is when the potentially cancerous cells in a dog's bone marrow are a relative mix of cancerous and healthy cells.

If your dog is able to retain enough of these healthy cells, without them becoming cancerous, the chances of survival are greatly increased. Chronic Lymphoid Leukemia occurs when a single lymphocyte cell becomes cancerous, and begins to replicate over time. These cancerous cells replace normal lymphocytes, which causes cancer in the bone marrow and lymph nodes. This type of leukemia is commonly associated with secondary infections, since the lack of normal lymphocytes means that a dog’s immune system response is significantly decreased.

Chronic Myeloid Leukemia (also called CML)

This type of canine leukemia is characterized by a subsequent increase in myeloid cells in a dog’s bone marrow. These cells also begin to increase in number in the bloodstream. This is also called a "clonal bone marrow stem cell disorder" by some veterinarians. This means that mature granulocytes are produced, and chromosomal translocation occurs. The type of chromosomal translocation that occurs with chronic myeloid leukemia involves a chromomosome called the “Philadelphia Chromosome”.

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