Hematologic Malignancies II Flashcards
(85 cards)
What clinical microscopic finding is necessary for diagnosis of acute leukemia, but is not very well refined based on clinical course?
The rapid proliferation of blast clones found in the bone marrow or in peripheral blood.
Diagnostic criteria: >20% implies acute leukemia
Problem: (cut-off # is arbitrary)
Immunophenotyping (IDing a cell based on surface proteins with Abs) is helpful in Dx but has a limitation:
The problem with immunophenotyping by itself is that many leukemias (and other hematologic malignancies) break the rules – their immunophenotype appears to be mixed. So immunophenotype BY ITSELF did not provide us with a very good diagnostic system, although it is an essential PART of our current diagnostic workup.
Let’s play “Identify That Immunophenotype, Bro!”
CD34+
blasts
Let’s play “Identify That Immunophenotype, Bro!”
CD34+, CD33+
myeloid blasts
Let’s play “Identify That Immunophenotype, Bro!”
Tdt+, CD10+
lymphoid blasts
Let’s play “Identify That Immunophenotype, Bro!”
CD19+, CD20+
mature B-lymphocytes/lymphoma
Let’s play “Identify That Immunophenotype, Bro!”
CD3+, CD5+
mature T-lymphocytes/lymphoma
** remember, CD3+ is the TCR! **
Let’s play “ID That Cancer Based on the Genotype, Bro!”
PML-RARA
Then name the translocation!
AML subtype
t(15;17)
Let’s play “ID That Cancer Based on the Genotype, Bro!”
RUNX1-RUNXT1
Then name the translocation!
AML subtype
t(8;21)(q22;a22)
Let’s play “ID That Cancer Based on the Genotype, Bro!”
TEL-AML1 (ETV6-RUNX1)
Then name the translocation!
ALL subtype (I know, WTF assholes?!) t(12;21)(p13;q22)
Let's play "ID That Cancer Based on the Genotype, Bro!" FLT3 mutation (+)
AML subtype
Why is cytogenetics a better method for Dxing cancer?
Advantages:
Increased prognostic value
Predicts response to therapy
Identifies molecular targets for therapy development
Outline the current method for Dxing acute leukemias.
Basts > 20% in blood/bone marrow? Yes: acute leukemia No: cytogenetics Cytogen shows mutations/fusions of one of the 3 major types: acute leukemia No: something else
When Dx’d with acute leukemia, next step is detailed immunophenotype. May also require FISH or sequence-based studies.
List the 3 AML subtypes Dx’d by genetics alone, regardless of blast count.
RUNX1-RUNX1T1
CBFB-MYH11
t(15;17) PML-RARA (APL)
Explain how the PML-RARA subtype (APL) of AML causes cancer (responsible for 5-8% of AML cases) and what simple utility is used to send PML-RARA into clinical remission.
AML with t(15;17) PML-RARA (called APL) causes a dominant negative blockade of normal RARA that inhibits granulocyte differentiation.
PML-RARA itself can be blocked with a retinoic acid analog (all trans retinoic acid or ATRA)
ATRA induces differentiation of the blasts to granulocytes, CLINICAL REMISSION
How does t(15;17) PML-RARA (APL) present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
clinical presentation: severe thrombocytopenia
Morph: Big blasts, cleaved “bat wing” nuclei, many cytoplasmic granules, auer rods in stacks.
Immuno: weak/absent CD34, HLA-DR
CD13+, CD33+
Prognosis is good if you make the Dx early.
How does t(8;21)(q22;a22) RUNX1-RUNX1T1 present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
clinical presentation: younger pts, kids Morph: some maturation to myelocytes. Occasional crystallization of granule contents (auer rods) Immuno: CD34+, HLA-DR+, CD13+ CD33 weak Prognosis: good response to chemo
Describe the pathogenesis of t(8;21)(q22;a22) RUNX1-RUNX1T1.
5% of AML cases.
Fusion protein of 2 transcription factors (similar to PML). Runx1 is part of a heterodimeric transcription factor called Core binding factor (CBF)
Describe the pathophysiology of inv(16)(p13.1;q22) aka t(16;16)(p13.1;q22) CBFB-MYH11 How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
5-8% of AML cases
Path: Dominant negative repressor of myeloid maturation
CBFB is the other component of the CBF heterodimer!!
clinical presentation: younger pts, kids
Morphology: Mixed granulocyte-monocyte features (“Myelomonocytic”) Increased eosinophils in blood and marrow
Immunophenotype:
CD34+, CD117+ (blasts)
CD13+, CD33+ (granulocytes)
CD14+, CD11b+ (monocytes)
Prognosis: Better than most if “risk adapted” therapy is used
Acute myeloid leukemias that are well-characterized based on genetic subtyping make up only ___% of cases.
15-20%
AMLs with normal cytogenetics make up almost ___% of cases, and they trend toward these morphologic types:
50%
any morphologic type: granulocytes, monocytes, red cell precursors, megas
What determines how cytogenetically normal AMLs are treated?
depends on the results of targeted sequencing studies
How do cytogenetically normal AMLs present clinically?
Describe the morphology:
Describe the immunophenotype:
Prognosis?
Clinical Presentation: Any age group
Morphology: Undifferentiated, or variably granulocytic, or monocytic/monoblastic
Immunophenotype: Blast markers (CD34, CD117)+
typically CD33+
Prognosis: Depends on molecular genetics
The genes NPM1, FLT3, and CEBPA are significant in AML why?
the molecular findings in these cases are predictive of what kind of therapy they will respond to