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The truth about chronic myelogenous leukemia: What is its mysterious cause?
Chronic myelogenous leukemia (CML) is a cancer that affects white blood cells and is characterized by the proliferation and uncontrolled growth of myeloid cells in the bone marrow. The disease is usually divided into three stages when diagnosed, from the chronic stage to the accelerated stage, and finally to the crisis. The changes in each stage are related to the genetic abnormalities of the cells. According to reports, CML mainly affects middle-aged and elderly men, and the key factor in its pathogenesis is the so-called Philadelphia chromosome.
Due to the uncontrollable proliferation of white blood cells during the development of chronic myelogenous leukemia, many patients have reached the accelerated stage of the disease when diagnosed.
Symptoms and diagnosis
The manifestations of CML often depend on the stage at diagnosis. About 90% of patients are diagnosed in the chronic phase, when symptoms may be mild or asymptomatic, and elevated white blood cell counts are often found during routine examinations. As the disease progresses, patients may experience symptoms such as hepatosplenomegaly, loss of appetite, and night sweats. In the process of confirming the diagnosis, a complete blood test and bone marrow biopsy are usually performed, and ultimately cytogenetics is relied upon to confirm the presence of the Philadelphia chromosome.
Key to the diagnosis of chronic myelogenous leukemia is the identification of chromosomal abnormalities, specifically the Philadelphia chromosome, the presence of which leads to the inactivation of key tumor suppressor genes.
Causes and risk factors
The exact cause of CML remains unclear in most cases. However, known risk factors include age and gender, with the disease being more common in men. Recent studies have shown that among survivors of nuclear bombings such as Hiroshima and Nagasaki who were exposed to radiation, the incidence of CML increased 50-fold and peaked about ten years after exposure.
With the advancement of genetics, the diagnosis rate of CML has increased. During this period, improvements in medical technology have greatly improved the survival rate of patients.
Pathophysiology
CML is the first cancer to be clearly linked to a specific genetic abnormality, the Philadelphia chromosome, an aberration that promotes the creation of the BCR-ABL fusion gene, which encodes a tyrosine kinase . This kinase continuously activates cell proliferation signals, causing cells to continue dividing and inhibiting DNA repair, leading to genome instability. The combined effects of these mechanisms exacerbate the development of CML.
Treatment methods
Currently, the main treatment for CML is the use of targeted drugs, namely tyrosine kinase inhibitors (TKIs). Since their introduction in 2001, these drugs have brought about significant improvements in survival rates and quality of life. The new generation of TKIs, including dasatinib and nilotinib, are specially developed to overcome patients' resistance to imatinib.
Prognosis
With the introduction of TKIs, the median survival time of CML patients has been significantly prolonged. It is reported that among patients using imatinib, the survival rate after five years is as high as 89%, and in some data, the survival rate is even close to that of the general population. This achievement changes the life story of CML patients.
The treatment of chronic myelogenous leukemia reflects how modern medicine uses genetic technology to achieve better efficacy and improve patients' quality of life.
Although significant progress has been made in the current understanding and treatment of CML, there are still many unsolved mysteries about its causes. Does this make us rethink how genes and environment work together in the development of cancer?
