What is acute lymphoblastic leukemia (ALL)?

Acute lymphoblastic leukemia (ALL) is a common malignant hematologic disorder. It may cause symptoms such as pallor, dizziness, fatigue, nausea, vomiting, blurred vision, fever, palpitations, anorexia, and skin petechiae or ecchymoses. When ALL infiltrates extramedullary tissues, additional manifestations may include epistaxis or gingival bleeding, hepatosplenomegaly and lymphadenopathy, bone and joint pain, and testicular enlargement. So, what exactly is ALL? The following section provides a detailed explanation.

ALL is a clinical syndrome resulting from the malignant clonal proliferation of leukemic cells, predominantly affecting children. Based on lymphocyte diameter, it is classified into three subtypes: L1, L2, and L3. Chemotherapy is the first-line treatment. Historically, vincristine combined with prednisone was the standard regimen; however, with advances in medical science, current protocols often incorporate additional agents such as L-asparaginase and cyclophosphamide. Notably, the remission rate for pediatric ALL now exceeds 80%. For eligible patients, allogeneic hematopoietic stem cell transplantation remains an important therapeutic option.

Knowledge Expansion: Etiology of ALL

1. Viral Infection

Adult T-cell leukemia can be caused by human T-lymphotropic virus type I (HTLV-I). After infecting the host, endogenous viruses integrate into and remain latent within host cells. Under certain physical or chemical stimuli, these latent viruses may become activated and expressed, thereby triggering leukemogenesis. Exogenous viruses, transmitted horizontally from external sources, can directly induce disease.

2. Physical Factors

These primarily include ionizing radiation such as X-rays and gamma rays. Studies indicate that large-area, high-dose radiation exposure can suppress bone marrow function and impair immune competence, leading to DNA mutations, breaks, and recombination—events strongly associated with leukemogenesis. Additionally, certain hematologic disorders—including myelodysplastic syndromes and lymphomas—may progress to leukemia over time.

3. Chemical Factors

Prolonged exposure to benzene and benzene-containing organic solvents, use of etretinate (formerly known as ethyl bis(morpholinoethyl)amine), and administration of antineoplastic agents—including alkylating agents and topoisomerase I inhibitors—can all predispose individuals to leukemia. Furthermore, familial leukemia accounts for approximately 0.7% of all leukemia cases; individuals with inherited genetic defects—such as those with congenital aplastic anemia—are also at increased risk.

The above provides an overview of acute lymphoblastic leukemia. We hope this information is helpful to you.