AML Foundations Flashcards
what does AML stand for?
acute myeloid leukemia
acute = able to quickly progress
myeloid = arising from a non-lymphoid lineage
leukemia = cancer of the blood
what is AML?
AML is a cancer of the blood arising from myeloid precursor cells that has the possibility to progress quickly if left untreated
what population is AML most common in?
most commonly seen in adults over the age of 45
how do definitely diagnose AML?
a blood smear or bone marrow biopsy must show ≥ 20% blasts or blast equivalents
what’s the main morphologic feature in AML?
abundance of myeloblasts
blasts are the earliest most immature precursor cells of a lineage
they usually have giant nucleus compared to the cytoplasm , fine smooth chromatin and visible nucleoli
what is a blast equivalent?
in some types of AML, the malignant cell is a little more mature than a blast
ex. i
n acute promyelocytic leukemia, for example, there are a ton of malignant promyelocytes (but not very many myeloblasts)
in these types of AML, we use the term “blast equivalent” instead of blasts for whatever immature call that is proliferating the most
why would someone with AML show symptoms of bone marrow failure?
patients with AML must have a bone marrow biopsy or blood smear showing ≥ 20% blasts or blast equivalents
so they’re gonna show symptoms of bone marrow failure because their BM is busy erroneously producing malignant cells and does not have the resources or space to create normal amounts of WBCs, RBCs, or platelets
what will the CBC of someone will AML show?
neutropenia = low neutrophils = increased risk of infection
thrombocytopenia = too few platelets = increased risk of bruising and bleeding
anemia due do too few RBCs
what does the blood smear of an AML patient show?
at least 20% blasts
cells containing Auer rods
what are Auer rods?
cytoplasmic inclusions that are formed from the abnormal fusion of azurophilic, or primary, granules
azurophilic granules are contained in neutrophils, which are formed from myeloid precursor cells.
literally lok like bars sticking out of the nucleus
how do you classify AML into subtypes?
there’s 8 FAB classifications of AML that depend on what type of cells the disease developed from and how mature the cells were at diagnosis
AML doesn’t grow like a solid tumor so it’s not staged like most cancers
classification of AML depends on other information such as the subtype, the patient’s age, and other lab results
what is the M0 FAB subtype?
Acute myeloblastic leukemia with minimal differentiation
what is the M1 FAB subtype?
Acute myeloblastic leukemia without maturation
what is the M2 FAB subtype?
acute myeloblastic leukemia with maturation
what is the M3 FAB subtype?
Acute promyelocytic leukemia (APL)
what is the M4 FAB subtype?
Acute myelomonocytic leukemia
what is the M5 FAB subtype?
Acute monocytic leukemia
what is the M6 FAB subtype?
acute erythroid leukemia
what is the M7 FAB subtype?
acute megakaryoblastic leukemia
what cell type of FAB subtypes M0-M3 involve?
neutrophil precursors
but myeloid progenitor cells can form RBCs, platelets, basophils, neutrophils, eosinophils, and monocytes.
so it makes sense that it is possible for AML to arise from any of these cell lines
what cell type of FAB subtypes M4-M5 involve?
monocytic precursors
what’s the WHO system of classifying AML?
a newer system to classify AML into five categories, which take into consideration genetics (chromosome translocations), immunophenotype, morphology, and clinical features
what is the WHO system of classifying AML?
- AML with recurrent genetic abnormalities
- AML with myelodysplasia-related changes
- Therapy-related AML
- AML, not otherwise specified
- Myeloid sarcoma
How does the classification of AML differ from the FAB and the WHO classification systems?
The FAB system classifies AML based on cellular morphology while the WHO system classifies AML based on genetics, such as chromosomal translocations, as well as immunophenotype and morphology.
what’s the most well-known FAB subtype?
M3, aka acute promyelocytic leukemia (APL)
what causes APL?
most common AML
APL is due to a translocation between chromosomes 15 and 17 [t(15;17)] and may account for 5-20% of all cases of AML
how do you treat APL?
all-trans retinoic acid, a form of vitamin A
it prompts differentiation of the WBCs, effectively putting an end to the predominance of blast cells and, therefore, the cancer
Acute promyelocytic leukemia (AML subtype M3) is due to a translocation between which two chromosomes?
APL is due to a translocation between chromosomes 15 and 17. This is written as t(15;17).
