Hematologic Malignancies I (part 2) Flashcards
What is the most common form of acute leukemia in adults?
AML
There are 14+ subtypes of AML. Four of these are classified by genetics alone, regardless of blast count. What are the three we need to know?
- t(8,21)(q22:q22): RUNX1-RUN1T1
- inv(16)(p13.1:q22) or t(16, 16)(p13.1:q22) CBFB-MYH11
- t(15,17)(q22;q12) PML-RARA
There are 14+ subtypes of AML. Four of these are classified by genetics alone, five are classified by different criteria. What is it?
5 subtypes with characteristic cytogenetic findings and >20% Blast count
What is AML with t(8,21)(q22:q22)?
Fusion protein of two transcription factors (RUNX1-RUN1T1). 5% of AML cases
It’s a dominant negative repressor of myeloid maturation
Is AML with t(8,21) class 1 or 2 mutant?
Class II that requires concurrent class I mutation
Does AML with t(8,21) present in kids or adults typically?
Younger pts/kids
What is the morphology of AML with t(8,21)?
Some maturation to myelocytes. Occasional crystallization of granule contents (Auer rods)
What is the immune phenotype of AML with t(8,21)?
CD34, HLA-DR+, CD13, CD33 weak
What is the prognosis of AML with t(8,21)?
Good response to chemo
What is AML with t(15,17)?
Fusion of two transcriptions factors PML with RARA (retinoic acid receptor). 5-8% AML cases
What is the result of the AML with t(15,17) fusion protein?
Dominant neg. blockade of normal RARA. Inhibits granulocyte differentiation
Why is AML with t(15,17) a good example of hoe genetics lead to clinical utility?
PML-RARA itself can be blocked with RA analogue (All Trans Retinoic Acid or ATRA) which results in ATRA inducing differentiation of the blasts to granulocytes -> Clinical Remission
What class mutation is AML with t(15,17)?
Class II that requires concurrent class I
What is the clinical presentation of AML with t(15,17)?
DIC. Severe thrombocytopenia
What is the morphology seen in AML with t(15,17)?
Big blasts, cleaved “bat wing” nuclei, many cytoplasmic granules, Auer rods in stacks
What is the immunophenotyping of AML with t(15,17)?
Weak/absent CD34, HLA DR, CD13, CD33
What is the prognosis of AML with t(15,17)?
Good, if diagnosis can be made
Can translocations to RARA from other places produce the same leukemia [AML with t(15,17)]?
Yes. BUT, they may not respond to ATRA
What is AML with inv(16) or t(16,16)?
Fusion protein of transcription factor (CBFB) with MYH11. 5-8% of AML cases
What class is AML with inv(16) or t(16,16) in?
Class II that probably requires concurrent class I
Does AML with inv(16) or t(16,16) present clinically in kids(younger pts) or adults?
Younger pts/kids
What is the morphology of AML with inv(16) or t(16,16)?
Mixed granuloctye-monocyte feature (myelomonocytic). Increased Eosinophils in blood and bone marrow
What is the immunophenotype of AML with inv(16) or t(16,16)?
CD34, CD17 (blasts), CD13, CD33 (granulocytes), CD14, CD11b (monocytes)
What is the prognosis for AML with inv(16) or t(16,16)?
Variably poor; optimal with high dose cytarabine
What is the clinical presentation of AML with normal cytogenetics?
Any age group. 40-50% of cases. They can trend toward any morphologic type (granulocytes, monocytes, red cell precursors. megakaryocytes)
What is the morphology of AML with normal cytogenetics?
Undifferentiated or variably granulocytic or monocytic/monoblastic
What is the immunophenotype of AML with normal cytogenetics?
Blast markers (CD34, CD117). Can show any lineage markers
What is the prognosis of AML with normal cytogenetics?
Depends on the molecular genetics
What is the prognosis for AML with normal cytogenetics in individuals who have NPMN1 or CEBPA+, FLT3-ITD-?
60% 4 yr survival. BM transplant doesn’t help
What is the prognosis for AML with normal cytogenetics in individuals who have FLT3-ITD+ or NPMN1-, CEBPA-, FLT3-ITD-?
About 29% 4 yr survival. BM transplant helps
For ALL, are two classes of mutations/translocations required?
Maybe. What is known is that there are a number of transcription factors which regulate early B cell development that are involved in the genesis of ALL
What are some key markers of early, middle, and late B cell development? Which myeloid markers can they express?
CD34, Tdt, CD19, CD10, muCD20. They can express myeloid markers CD13, CD33
Are the myeloid markers expressed in ALL a major contributor to clinical management?
No
What is the clinical presentation of ALL?
75% of ALL cases occur in kids under 6. There is about an 80% cure rate in kids, but 50% for adults
What is the primary determinant for the clinical management of ALL?
Genetic characterization
What is ALL with t(9,22)?
Fusion protein of part of a serene kinase (BCR) to a tyrosine kinase (ABL1); Proliferation activator (class II equivalent) The IKZF1 transcription factor is mutated in 84% of cases; differentiation inhibitor (class I equivalent)
What is the clinical presentation of ALL with t(9,22)?
Older adults (25% of ALL cases); kids ,1 (2-4% of peds ALL)
What is the morphology of ALL with t(9,22)?
Big agranular blasts
What is the immunophenotype of ALL with t(9,22)?
CD10, CD19, Tdt
What is the prognosis of ALL with t(9,22)?
Poor
What is ALL with t(v;11q23); MLL rearranged?
Fusion of a transcription regulator (histone methyl transferase) to any of several partners. Inhibits differentiation (equivalent of class II mutation). Also found in AML
FTL4 mutation in 20% of cases (known class II mutation in AML)
What is the clinical presentation of What is ALL with t(v;11q23)?
Most common leukemia in kids <1
What is the morphology of What is ALL with t(v;11q23)?
Big agranular blasts
What is the immunophenotype of ALL with t(v;11q23)?
CD10-, CD19+, TdT+
What is the prognosis of ALL with t(v;11q23)?
Poor
What is ALL with t(12, 21)(p13,q22) TEL-AML1 (ETV6-RUNX1)?
Fusion protein that acts as a dominant neg. transcription factor. Inhibits differentiation (equivalent of a class II mutation).
28% of ALL with t(12, 21) show what other deletion?
Pax5 deletion (predicted to inhibit differentiation)
What is the clinical presentation of ALL with t(12, 21)?
Kids. 25% of pediatric B-ALL
What is the morphology of ALL with t(12, 21)?
Big agranular blasts
What is the immunophenotype of ALL with t(12, 21)?
TdT+. CD34+, CD20-
What is the prognosis of ALL with t(12, 21)?
Good. 90% cure rate
Is genetics currently a good clinical guide to the management of T-ALL?
Nope
What results in a comparable survival rate to B-ALL with kids?
More intense chemotherapy regimen
Genetically, what do most T-ALL have?
Translocation of an oncogene to a T-cell receptor promoter, 3 TCR loci, multiple possible partners