Hematologic Malignancies II Flashcards
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
How do AMLs with a complex karyotype present clinically? Describe their karyotype: Describe the morphology: Describe the immunophenotype: Prognosis?
AML with a complex karyotype (5-10% of AML cases)
Clinical Presentation: Any age group
Karyotype: three or more cytogenetic findings such as translocations, trisomies, or monosomies. These cases often show deletions or other mutations affecting TP53, conferring genetic instability.
Morphology: Undifferentiated, or variably granulocytic, or monocytic/monoblastic
Immunophenotype: Blast markers (CD34, CD117)+ typically CD33+
Prognosis: Poor
Time for some epidemiology:
Describe the clinical presentation of ALL. Who gets it? What is the prognosis in kids and adults?
Clinical Presentation: 75% of ALL cases occur in kids under 6 and over 80% of acute leukemias in kids are ALL
~80% cure rate in kids, ~50% in adults
Regarding ALL:
Does BCR-ABL1 carry a good or bad prognosis?
Bad
Regarding ALL:
Does MLL rearrangement carry a good or bad prognosis?
Bad
Regarding ALL:
Does TEL-AML1 (ETV6-RUNX1) carry a good or bad prognosis?
Good
Regarding ALL: Do hyperdiploid (>50 chromosomes) cases carry a good or bad prognosis?
Good
With regards to ALL: Describe the pathophysiology of TEL-AML1 (ETV6-RUNX1) How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion protein that acts as a dominant negative transcription factor with multiple effects on gene expression; in general THESE BLOCK MATURATION
Clinical presentation: kids. 25% of ped. B-ALL
Morph: big Agranular blasts
Immuno: **TdT+, **CD34+, **CD10+, CD20-
Prognosis: Good! 90% cure rate
With regards to ALL: Describe the pathophysiology of t(9;22) BCR-ABL1 How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion protein of part of a serine-threonine kinase (BCR) to a tyrosine kinase (ABL1). PROLIFERATION ACTIVATOR. IKZF1 transcription factor mutated in 84% of cases DIFFERENTIATION INHIBITOR
Clinical presentation: Older adults (25% of ALL cases) Kids < 1yo (2-4% of peds ALL)
Morph: big Agranular blasts
Immuno: CD10+, **CD19+, TdT+
Prognosis: Poor
With regards to ALL: Describe the pathophysiology of an MLL rearrangement How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: Fusion of a transcription regulator (histone methyl transferase) to any of severa; partners. INHIBITS DIFFERENTIATION (also found in AML)
FLT3 mutations in 20% of cases (ENHANCES PROLIFERATION)
Clinical presentation: Most common leukemia in kids < 1yo
Morph: big Agranular blasts
Immuno: CD10-, CD19+, TdT+
Prognosis: Poor
With regards to ALL: Describe the pathophysiology of T-ALL How does it present clinically? Describe the morphology: Describe the immunophenotype: Prognosis?
Patho: most have a translocation of an oncogene to a T-cell receptor promotor (any of the three TCR loci in the genome). Multiple possible partners.
** COMMON MOTIF FOR LYMPHOID MALIGNANCIES, ONCOGENE TRANSLOCATION TO AN Ig or TCR Promotor **
Clinical presentation: Kids. 25% of peds B-ALL. Often with thymic mass or lymph node, spleen involvement.
Morph: big Agranular blasts
Immuno: TdT+, CD3+, CD5+; can express myeloid or B-cell antigens as well
Prognosis: “high risk” require aggressive chemo, results in survival rate comparable to that of kids with B-ALL.