Leukemia

The main leukemias are:
-Acute lymphoblastic leukemia (ALL) – is the most common type of leukemia in pediatric age. ALL starts in the bone marrow, and most of the time, the leukemic cells invade the blood fairly quickly but can also spread to other parts of the body. 
-Acute myeloid leukemia (AML) – affects both adults and children. It results from the malignant transformation and uncontrolled proliferation of an abnormally differentiated long-lived myeloid progenitor cell resulting in high circulating numbers of immature blood cells and replacement of the bone marrow with malignant cells.
-Chronic lymphoid leukemia (CLL) – mainly affects older adults and and accounts for about a third of all leukemias. It is a type of leukemia that starts in the white blood cells in the bone marrow.
-Chronic myeloid leukemia (CML) – mainly affects adults and does not affect children. Occurs when the pluripotent stem cell undergoes malignant transformation and clonal myeloproliferation, causing overproduction of immature granulocytes.

The ALL is the most common type of acute leukemia in the pediatric population and is responsible for the majority of cancer deaths in children. This type of leukemia varies with age and affects 20%-30% of children with cancer, representing approximately 25% of diagnoses in children under 15 years of age.

AML is a highly heterogeneous disease, presenting as de novo or secondary disease, therapy-related or post-antigenic hematologic disorder. The incidence of disease onset increases with age, with the median age at diagnosis of AML being 67 years, with approximately one-third diagnosed over the age of 75. Conventional therapy for acute myeloid leukemia consists of induction of remission with cytarabine and anthracycline-containing regimens, followed by consolidation therapy, including allogeneic stem cell transplantation, to prolong remission. In recent years, there has been a greater understanding of the pathophysiology of AML, which has facilitated the development of new molecularly targeted therapies and the implementation of a personalized, risk-adapted approach to treatment.