JAK2
GENE
Piecing together the FACTS ABOUT PV
What is polycythemia vera?
Is PV cancer?
PV is a rare, slow-growing blood cancer. It’s part of a group of blood cancers known as myeloproliferative neoplasmsA group of cancers that start in the bone marrow, where blood cells are made. (my-e-lo-pro-lif-er-a-tive neo-plasms), or MPNs.
How does PV impact blood cellsTypes of cells that carry oxygen and nutrients to support various functions in the body. They begin as stem cells in the bone marrow and mature into red blood cells, white blood cells, and platelets.?
PV starts in the bone marrowThe soft, spongy tissue inside bones that is responsible for making billions of new blood cells every day. where stem cellsA special type of cell that can develop into many different types of cells in the body. make all your body’s blood cells, including red blood cellsA common type of blood cell that carries oxygen from the lungs to all parts of the body., white blood cellsA type of blood cell made in the bone marrow that helps the body fight infections and disease., and plateletsSmall cell fragments made in the bone marrow that help form clots and stop or prevent bleeding..
Normally, your body keeps all types of blood cells in a healthy balance. With PV, however, your body produces too many red blood cells and may also create excess white blood cells and platelets.
Having too many blood cells causes the blood to thicken and increase in volume (called hyperviscosityWhen the blood thickens and increases in volume so much that it doesn’t flow through your blood vessels properly.), which can slow down blood flow and increase the risk of blood clots and strokes. Your doctor may refer to these as “thrombotic eventsThe formation of a blood clot in a blood vessel or the heart, which can block blood flow..”
Assessing your risk level
Whether you have low-risk or high-risk PV, it’s important to be proactive and
talk to your doctor about your long-term treatment goals.
Less than
60 years of age
no prior history of thrombotic event
Over
60 years of age
or
prior history of
thrombotic event
Hear real PV perspectives
What causes PV and how common is it?
Causes of polycythemia vera
PV happens when stem cells in the bone marrow develop a mutationAny change in the DNA sequence of a cell. It can be inherited from your parents or caused by external factors, such as chemicals in your environment. that leads to the overproduction of blood cells.
- Over 90% of people with PV have a mutation in the JAK2A gene that makes a protein to help control the number of red blood cells, white blood cells, and platelets made in the bone marrow. gene
- The JAK2 gene promotes cell growth and helps control the number of blood cells that are made in the bone marrow
Is PV genetic or inherited?
Typically, PV is not inherited. The JAK2 mutationA rare mutation in the JAK2 gene that can cause the body to make too many blood cells. usually happens during a person’s lifetime for unknown reasons.
How common is PV?
What are the signs and symptoms of PV?
Because some people with PV experience vague or mild symptoms that develop slowly over many years, it can be easy to ignore them. That’s one of the reasons why PV is sometimes only discovered during routine blood tests.
So, if you think you have PV or have already been diagnosed, it’s important to tell your doctor about all the symptoms you experience—whether you think they’re related to PV or not. That way, they can put together a care plan that considers all the pieces of your PV.
Common PV symptoms
- Headache
- Dizziness
- Blurry vision
- Unusual bleeding or bruising, including nosebleeds or bleeding gums
- Itchy skin (pruritus), especially after a hot bath or shower
- A reddened or purplish skin rash, especially on the palms, ear lobes, nose, and cheeks
- A feeling of fullness soon after eating
- Bloating or pain in your upper left abdomen
- Fatigue or
low energy - Shortness of
breath and difficulty
breathing when lying down
- Painful swelling of one joint (often the big toe)
- Numbness, tingling, or a burning sensation in the hands, feet, arms, or legs
Making sense of PV risks and complications
PV doesn’t present in stages like many other cancers. It’s a chronic, progressive cancer that may change or get worse over time. That’s why it’s so important to proactively manage your condition for the long term.
Understanding both the short- and long-term risks can help you and your doctor create a care plan that may help reduce the chances of serious complications like thrombotic events (blood clots) and slow disease progression.
Risk of blood clots with PV
Reduced blood flow due to thickening of the blood in PV can increase the risk of developing blood clots, which can cause stroke, chest pain (angina), heart attack, deep vein thrombosis (DVT), and pulmonary embolism.
- Blood clots occur in about 30% of people with PV even before the diagnosis is made
- During the first 10 years after a diagnosis, 40%-60% of untreated people with PV may develop blood clots
Managing PV progression
Because PV can turn into more aggressive cancers over time, it’s important to talk to your doctor about ways to help manage your risk. These risks include:
Bone marrow is the soft, spongy tissue that fills the center of most bones. When PV is not well-controlled, it may transform into MF, a rare cancer that causes scarring in the bone marrow.
- When this scarring occurs, the marrow can no longer make enough healthy blood cells, which results in low levels of functioning red blood cells (anemiaA condition when you don’t have enough healthy red blood cells to carry oxygen throughout your body.), platelets (thrombocytopeniaA condition that occurs when your bone marrow doesn’t make enough platelets (thrombocytes). It can result in easy bruising or bleeding.), and white blood cells (leukopeniaA low white blood cell (leukocyte) count.)
- Approximately 10% of people with PV may develop MF within 10 years of diagnosis
In some people, PV can advance into acute myeloid leukemiaA rare, fast-growing cancer that affects your bone marrow and blood, and can spread to other parts of the body. (AML), an aggressive type of blood cancer that grows quickly and results in too many immature white blood cells in the blood and bone marrow.
- AML often quickly moves from the bone marrow into the blood and can sometimes spread to other parts of the body
- Between 2%-14% of people with PV may develop AML within 10 years of diagnosis
The high turnover of red blood cells with PV leads to higher-than-normal uric acid production, which is associated with kidney stones. Passing kidney stones can be extremely painful, but the stones usually don’t cause permanent damage.
The spleen often becomes enlarged in people with PV because it’s working overtime to filter out a greater number of blood cells than normal. An enlarged spleen, or splenomegaly (splee-nuh-MEG-uh-lee), may:
- Cause a bloated or full feeling in the abdomen
- Lead to more frequent infections, anemia, and/or increased bleeding
- Rupture and cause life-threatening bleeding in the abdominal cavity
The high turnover of red blood cells with PV leads to higher-than-normal uric acid production, which can cause an inflammation of the joints called gout.
- Gout can cause intense joint pain, most commonly in the big toe, ankles, knees, elbows, wrists, and fingers
- Pain is usually most severe within the first 4 to 12 hours after it begins, but some joint discomfort may last from a few days to a few weeks
- As gout progresses, attacks may last longer and limit your range of motion
Peptic ulcers are open sores on the lining of the gastrointestinal tract. Left untreated, they can cause internal bleeding, a hole in the stomach wall, or an obstruction in the digestive tract causing you to become full easily, vomit, and/or lose weight.