Leukemia is a blood cell cancer that affects both blood and bone marrow. It affects the circulatory, respiratory, and skeletal systems. It arises in the two main types of white blood cells: Lymphoid and myeloid cells, accordingly called lymphoblastic leukemia and myeloid leukemia. There are many types of leukemia, but the most common types affect white blood cell growth as red blood cells are rarely affected. Depending on the type of leukemia, different genes can be mutated.The CEBPA gene is involved in acute myeloid leukemia which can be inherited. Additionally, in chronic myelogenous leukemia, the oncogene is called BCR-ABL, which causes the overproduction of white blood cells.
WHAT IS THE EFFECT ON CELL GROWTH?
Depending on the type of leukemia, it can affect cell growth in several ways. To categorize it, there are acute (fast-growing) and chronic (slow-growing) leukemias. Acute leukemia cells are hyperproliferative, or the cell numbers increase rapidly through division, and these cells have high amounts of cyclins, so the cells ignore stop signals of the cell cycle and continuously divide. In contrast, chronic leukemia is a disease with a low proliferative activity and the cancer cells arrest in G0 and G1 phase.
WHAT CAUSES LEUKEMIA?
Since leukaemia mainly disturbs white blood cell growth the most, it starts off in the bone marrow, typically caused by a gene mutations which lead to activation of oncogenes that can be inherited or can be by environmental factors such as traffic air pollution, high doses of radiation, exposure to chemicals such as benzene, smoking, and certain types of chemotherapy agents. A viral infection of the bone marrow cells can also cause lymphocytic cells to abnormally grow. There are some unknown factors for leukemia.
IS THERE A WAY TO PREVENT IT?
Most types of leukemia have no effective way to prevent them except for some types such as acute myeloid leukemia, that can be inherited, by doing genetic screenings on the blood to see if the patient is susceptible to the leukemia. Another way to prevent leukemia is through vaccination if it was caused by an viral infection. Actually, there are few ways to prevent leukemia since it is typically not inherited and most causes of leukemia are unknown.
DIAGNOSIS AND SYMPTOMS
Depending on the type of leukemia, the blood would contain an abnormal amount of white blood cells and have an abnormal morphology would suggest the signs of leukemia. Some symptoms of leukemia would include:
- Swollen lymph nodes (long term)
- Nose bleeds (short term)
- Bone pain (long term)
- Red spots on skin (long term)
- Severe infections (long term)
- Fatigue (short term)
- Fever (short term)
- Early satiety (short term)
- Loss of body weight (long term)
Blood tests and bone marrow needle biopsies can confirm if a patient suffers from leukemia. Sometimes if needed, a DNA sequence check would validate the diagnosis.
TREATMENT
Treatment methods include chemotherapy, immunotherapy, bone marrow transplantation, radiotherapy, and sometimes gene therapy. The most effective methods are immunotherapy which can use specific antibodies and/or the engineered immune T-cells to kill the cancer cells and bone marrow transplantation, a process to replace the unhealthy bone marrow with new, functioning bone marrow cells. These methods are the most effective, but take a few months to a year to undergo if the leukemia is caught early on. Other ways like chemotherapy that uses chemical agents to kill cancer cells, radiotherapy that uses radiation to break the DNA to kill cancer cells, or gene therapy that replaces mutated nucleotides in the gene sequence with normal ones. These treatment methods are effective in some cases, but immunotherapy and bone marrow transplantation are more potential. All these methods may be long term to sustain the survival of the patient, letting them live longer. Each method removes cancer cells so the healthy ones can continue the normal cell cycling (immunotherapy, chemotherapy, bone marrow transplantation, radiotherapy) or repair mutated genes (gene therapy), letting the cell cycle function normally. Unfortunately, some patients may relapse a year or so after cease of treatment.
PROGNOSIS
Prognostication varies between person to person, based on circumstances such as age, type, and how critical the cancer has become. Roughly 80% to 90% of adults who have leukemia will experience complete remissions sometime during current treatments, meaning the leukemia cells won’t be visible in the bone marrow and blood. Around half of these patients relapse during this process, so the overall cure rate drops to 40%. However, about 98% of children with lymphoblastic leukemia go into remission within weeks after starting treatment. 90% of the children can be cured and patients are considered cured after 10 years in remission.