Bone Marrow – Blood Cell Creation and Cancer

Introduction

Cancer is the uncontrolled growth of cells whose DNA expression has been damaged. Cancerous cells divide continuously, replacing normal tissue. Cancer, or neoplasms, new and abnormal tissue growth in some part of the body, can be benign or malignant.

While benign cancers remain localized to their originating tissue, malignant cancers can spread to other organs. Secondary growths or metastases are a serious complication of any anticancer therapy. A tumor is any clump of cells that fills up space and may or may not be malignant.

Benign growths or tumors usually are denoted by the suffix “-oma.” For instance, an adenoma is a benign growth of the adrenal cortex, a collection of hormone-producing cells near the kidney.

Malignant tumors are identified by the addition of the term “sarcoma” or “carcinoma.” Adenocarcinoma is a malignancy of the adrenal cortex, and Osteosarcoma is a type of bone cancer.

What is bone marrow

Bone marrow is a semi-solid flexible connective tissue in the spongy hollow portions of bones, primarily in the ribs, vertebrae, sternum, and bones of the pelvis. This hollow area is referred to as cancellous tissue due to its mesh-like and porous structure. 

Bone marrow in humans produces approximately 500 billion blood cells per day. In healthy mature adults, bone marrow accounts for roughly 5% of total body mass, so that a guy weighing 161 lbs. will have approximately 8 lbs. of bone marrow.

Hematopoiesis

The central location of new blood cell creation is in the bone marrow. There are two types of stem cells in bone marrow, mesenchymal and hematopoietic. It is from stem cells that the body generates all other cells that perform many important roles in our bodies. The process of stem cells developing into various blood cells is called HEMATOPOIESIS. 

Under the influence of tissue and hormonal factors, pluripotent hematopoietic cells can become any specific blood cell line in the blood system. Pluripotent refers to a cell’s ability to become different cells. These include red cells, which carry oxygen to your tissues, white blood cells or leukocytes necessary for your immune system, and platelets. 

Red and Yellow Marrow

Bone marrow is classified into two types: red marrow and yellow marrow. Yellow marrow has a greater proportion of fat cells than red marrow does. Both forms of marrow have blood vessels. All bone marrow is red at birth. As we age, a greater proportion of the marrow becomes yellow bone marrow. About half of the bone marrow in adults is red, while the other half is yellow.

The red marrow produces the bulk of red blood cells, platelets, and the majority of white blood cells, whereas the yellow marrow produces only a few. Everyone requires a constant cycle of blood cell production from their bone marrow throughout their lifetimes, as each blood cell has a finite lifespan. 

Healthy bone marrow creates enough cells to meet your body’s requirements. When the body requires extra oxygen, red cell production is raised; platelet production is enhanced when bleeding occurs, and white cell production is boosted when infection threatens.

Bone marrow cancer 

As with other cancers, bone marrow cancer begins when cells in the bone marrow begin to grow abnormally or rapidly. Bone marrow cancer, also called blood cancer, begins in the bone marrow but is NOT “bone cancer.”

The name of a particular cancer is given from the place it started. If it spreads to another part of the body, it still has the same name. For example, if breast cancer spreads (metastases) to the lungs, it is still called breast cancer.

There are two types of bone marrow cancer.

Multiple myeloma

Multiple myeloma is the most common kind of bone marrow cancer. Only one percent of all cancer cases in the United States are due to multiple myeloma. There are an estimated 4 to 5 new cases of this form of cancer per year. 

The cancer begins in the plasma cells. This is a kind of white blood cell that produces antibodies to defend the body against external intruders. Tumors develop when your body produces an abnormally high number of plasma cells resulting in bone loss and a weakened immune system.

The tumor, its products, and the host response result in several organ dysfunctions and symptoms that may include: 

  • Abdominal pain
  • Bleeding and bruising due to low blood platelets (thrombocytopenia)
  • Bone pain or weakened bones
  • Confusion due to high levels of calcium in the blood (hypercalcemia)
  • Dehydration
  • Drowsiness
  • Extreme thirst
  • Frequent urination
  • Infections due to shortage of normal white blood cells (leukopenia)
  • Kidney damage or kidney failure
  • Loss of appetite
  • Peripheral neuropathy, or tingling, due to nerve damage
  • Weakness and fatigue due to shortage of red blood cells (anemia)

Leukemia

Typically, leukemia affects white blood cells. The body generates aberrant blood cells that do not naturally die off. They swarm regular white blood cells, red blood cells, and platelets as their numbers increase, impairing their capacity to function.

There are various forms of leukemia classified mostly according to whether they are acute (rapidly developing) or chronic (slowly growing) and whether they begin in myeloid or lymphoid cells. 

Acute leukemia is characterized by immature blood cells termed blasts, and symptoms can manifest rapidly. Chronic leukemia is characterized by the presence of more mature blood cells. Because the symptoms might be modest at first, you may go years without realizing you have it.

Knowing the precise kind of leukemia enables clinicians to more accurately estimate each patient’s prognosis (prognosis) and choose the most appropriate therapy.

Signs and symptoms of leukemia include:

  • Bone pain
  • Bruising or bleeding easily, including frequent nosebleeds
  • Enlarged liver or spleen
  • Excessive sweating
  • Fever and chills
  • Frequent or severe infections
  • Night sweats
  • Swollen lymph nodes
  • Tiny red dots on the skin (petechiae)
  • Unexplained weight loss
  • Weakness and fatigue

The prognosis and survival rate for patients with bone marrow cancer are greatly improved by early identification. If you have some of these symptoms, see your doctor. Bone marrow and other blood cancers can be detected with standard physical examinations, blood and urine testing, and other diagnostic procedures.

 

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