Hematologic tumors can affect the patient’s blood cells and bone marrow. The bone marrow is the spongy soft tissue within the bone that has hematopoietic functions. In contrast, hematologic tumors cause abnormalities in the biological behavior of blood cells as well as in their function.
There are 3 types of blood cells in the body:
- White blood cells fight infection as part of the immune system.
- Red blood cells carry oxygen to tissues and organs throughout the body, and carry carbon dioxide produced by metabolism back to the lungs, where it is expelled through gas exchange.
- Platelets can contribute to blood clotting in case of injury.
There are 3 main types of clinical hematologic tumors:
- Leukemia
- Lymphoma
- Myeloma
The above hematologic tumors can cause the patient’s bone marrow and lymphatic system to produce blood cells that do not function properly, and they may act in different ways to affect different They may affect different types of leukocytes through different modes of action.
Leukemia
Patients with leukemia produce large numbers of non-functioning leukocytes. Depending on the type of white blood cells involved and whether they are fast-growing (acute) or slow-growing (chronic), there are four types of leukemia:
Acute lymphoblastic leukemia (ALL)
It starts with a type of white blood cell in the bone marrow called a lymphocyte. Patients will produce too many lymphocytes, which will crowd out healthy white blood cells. If left untreated, the disease will progress rapidly.
The risk is increased if you have:
- a brother or sister with acute lymphoblastic leukemia;
- previous chemotherapy or radiation therapy for another cancer;
- exposure to high doses of radiation in close proximity;
- Down syndrome or other genetic disorders.
Acute myeloid leukemia (AML)
Begins in the bone marrow cells. Normal bone marrow stem progenitor cells usually differentiate into white blood cells, red blood cells, and platelets. The development of AML results in a decrease in the number of all 3 types of healthy blood cells. Such leukemic cells can grow rapidly.
Acute myeloid leukemia mainly affects people over 65 years of age and is more common in men than women.
People with the following conditions are at higher risk:
- Past chemotherapy or radiation therapy for another cancer;
- Exposure to toxic chemicals such as benzene;
- Smoking;
- Concomitant blood disorders such as myelodysplasia or true erythroblastosis;
- Concomitant genetic disorders, such as Down syndrome.
Chronic lymphocytic leukemia (CLL)
is the most common type of leukemia in adults. Similar to acute lymphocytic leukemia, it originates from lymphocytes in the bone marrow, but grows more slowly. Many patients with chronic lymphocytic leukemia do not show more pronounced clinical symptoms until several years after progression of the disease.
CLL tends to occur in people over 60-70 years of age. A family history of hematologic tumors increases the risk of developing the disease. In addition, long-term exposure to chemicals, such as herbicides or pesticides, can lead to an increased risk of developing the disease.
Chronic myeloid leukemia (CML)
Similar to acute myeloid leukemia, it also originates from bone marrow cells. However, the cancerous cells grow more slowly.
Chronic myeloid leukemia is slightly more prevalent in the male population than in the female population. The clinical picture is mostly adult, with occasional development in children. The risk of development may be higher if there has been exposure to high doses of radiation.
Lymphoma
This is a tumor of the lymphatic system. The lymphatic system includes the lymph nodes, spleen, and thymus, and its main function is to store and transport white blood cells to help the body fight infection.
Lymphoma originates from a type of white blood cell called a “lymphocyte”. There are 2 main types of lymphoma:
Hodgkin’s lymphoma
Starts with immune cells called B lymphocytes or B cells. These cells produce proteins called antibodies that are used to fight pathogens. In patients with Hodgkin’s lymphoma, large lymphocytes called “Reed-Sternberg cells” are produced in the lymph nodes.
Non-Hodgkin’s lymphoma
begins with B cells or T cells. Non-Hodgkin’s lymphoma is more common than Hodgkin’s lymphoma.
Both of these 2 types of lymphoma can be divided into multiple subtypes, and subtypes are distinguished based on the site of tumor initiation in the patient, its biological behavior, and immune markers of tumor cells.
Lymphoma is most common in people aged 15-35 years and older than 50 years; people with a depressed immune system are more likely to develop lymphoma; infection with EBV (a member of the genus Lymphotropic Virus of the family Herpesviridae), human immunodeficiency virus (HIV), or Helicobacter pylori also increases the risk of developing lymphoma.
Myeloma
begins in B or T cells. Non-Hodgkin’s lymphoma is more common than Hodgkin’s lymphoma.
Both of these 2 types of lymphoma can be divided into multiple subtypes, and subtypes are distinguished based on the site of tumor initiation in the patient, its biologic behavior, and immunologic markers of tumor cells.
Lymphoma is most common in people aged 15-35 years and older than 50 years; people with a depressed immune system are more likely to develop lymphoma; infection with EBV (a member of the genus Lymphotropic Virus of the family Herpesviridae), human immunodeficiency virus (HIV), or Helicobacter pylori also increases the risk of developing lymphoma.