What are leukemia and its causes?
Leukemia occurs when certain cells become cancerous and infiltrate the bone marrow. Know what risk factors predispose to developing this blood cancer and the options to combat it.
The disease occurs due to an error in the maturation process of a stem cell into a white blood cell, which involves a chromosomal alteration that causes the affected cells to become cancerous and multiply incessantly, infiltrating the bone marrow, where they replace cells that make normal blood cells.
These cancer cells spread through the blood and invade other organs, such as the liver, kidneys, lymph nodes, spleen, and brain.
As the disease progresses, malignant cells interfere with the production of other types of blood cells, such as red blood cells and platelets, resulting in anemia and an increased risk of infection.
They are the most common neoplasms in childhood (about 25% of childhood cancers are leukemias), affecting males more frequently.
There do not appear to be substantial differences in leukemia prevalence between the different races or geographical areas, the rural or urban environment, or between the different social classes. However, depending on the type of leukemia, its appearance is more frequent at certain ages. For example, acute lymphocytic (lymphoblastic) leukemia usually occurs in children between three and five. Although it also affects adolescents, it is rare in adults.
Causes of leukemia
Although the cause of leukemias is not exactly known, it is known that several factors can cause the appearance of this disease.
- Environmental factors.
Regarding genetic factors with the development of leukemia, it is known that the disease is more frequent in twins than in the rest of the population, and suffering from genetic disorders such as Down syndrome and Fanconi syndrome is a factor risk associated with the development of leukemia.
People with weakened immune systems from chemotherapy or immunosuppressive drugs (given to patients who have undergone organ transplants) are also more susceptible to developing leukemia.
One of the most studied factors is environmental factors, especially exposure to ionizing radiation, chemicals such as benzene and certain drugs, and viruses.
The relationship between ionizing radiation and leukemia was discovered from nuclear accidents (explosions or incidents at nuclear power plants).
Various chemicals are also related to the disease’s appearance, especially some pesticides and other substances such as mustard gases used in World War I.
Types of leukemia
There are several criteria for classifying leukemias. One form of classification is based on its natural history:
- De novo: when they occur without a prior process that triggers the disease.
Another way of classifying them is based on the type of blood cell in which the malignant transformation begins and the disease progression speed. In the case of acute leukemias, their development is very rapid, while chronic leukemias progress slowly. Also, leukemias can be:
- Lymphoblastic: when they affect lymphocytes (a variety of leukocytes in the bone marrow).
- Myeloblastic or myelocytic: affecting the precursor cell of the myeloid series or red series (of red blood cells and platelets).
Acute lymphatic leukemia
In acute lymphatic leukemia, the cells that should be transformed into lymphocytes become cancerous and replace the normal cells of the bone marrow and spread to other organs (liver, spleen, kidneys, brain, lymph nodes). They continue to increase and cause diseases such as meningitis, anemia, kidney and liver failure, etc. It is the most common cancer in children.
Chronic lymphatic leukemia
Chronic lymphatic leukemia affects especially people over 60 years and men more than women. Cancerous lymphocytes increase in the lymph nodes, spread to the liver and spleen, and subsequently invade the bone marrow. This disease progresses slowly, and the prognosis depends on the number of lymphocytes in the blood and bone marrow, the severity of the anemia, and the patient’s immune system’s ability to fight infections that may be contracted.
Acute myeloid leukemia has characterized the myelocytes (the cells should become granulocytes), which become cancerous and normal cells replace bone marrow. As in the previous case, leukemic cells travel through the bloodstream and settle in other organs. They continue to grow and divide, causing various conditions (tumors, anemia, meningitis) and damaging other organs.
Chronic myeloid leukemia
Chronic myeloid leukemia, which affects people of all ages and sexes (although not common in young children), presents with anemia and thrombocytopenia (low blood platelet). It is estimated that it accounts for between 15 and 20% of all leukemia cases in adults. As the disease progresses, patients often present with fever, fatigue, weakness, loss of appetite and weight, enlarged lymph nodes, and bleeding.