Acute Leukemia - Simms Flashcards
List the 3 categories of WBC neoplastic proliferations
- lymphoid neoplasm
- myeloid neoplasm
- histiocytosis
______ block normal maturation, turn on pro-growth signaling pathways or protect cells from apoptosis.
Oncoproteins
Enhancement of self-renewal is a mutations property that allows activation of ______ → cell growth by enhancing MAPK.
tyrosine kinase which activates Ras
Proto-oncogenes are often activated in lymphoid genes by error during _______.
antigen receptor gene rearrangement/diversification
MC cause of proto-oncogene activation
- Germinal center B cells making an error during attempted class switching and somatic hypermutation
- V(D)J recombinase
V(D)J recombinase in precursor B/T cells modify Ig/T-cell receptor loci. They can accidentally _____ → proto-oncogene activation
join portions of other genes together
List 2 error made during somatic hypermutation and/or class switching
- MYC/Ig translocation → MYC
- BLC6 activation
How does BLC6 activation happen?
mistargeting by AID
How does MYC/Ig translocation occur?
AID translocated to transcriptionally active Ig locus
_____ are uncommon proliferative lesions of macrophages and dendritic cells
Histiocytosis
Lymphoid neoplasms include _____ (3) tumors
- B-cell
- T-cell
- NK cell
HIV leads to a risk of germinal B-cell lymphoma due to ____.
hyperplasia of germinal center
Chronic inflammation may lead to lymphoid neoplasms, almost always in the inflamed tissue. For example (2):
- H. pylori
- gastric B-cell lymphoma
T cells morphology of L2 (subtype of ALL) has grooves in the _____.
nuclei (highly irregular)
L3 (Burkitt type ALL) has _____ inside the cytoplasm.
vacuoles
Histochemistry of the ALL subtypes differentiates which 2 cell types?
- myeloid cells
- lymphoid cells (PAS +)
What is the main difference between Burkitt Leukemia & B-cell ALL?
- Burkitt: B cell precursors
- B-cell ALL: Mature B cells
(lends to prognosis)
Peak incidence for B-cell ALL is ______
3 y/o
How do you distinguish from T cell or B cell ALL?
- immunophenotyping
- cytogenetics
B-cell ALL is typically due to _____(2) mutations
- t(12;21)→RUNX1 & ETV6 loss of fxn
- t(9;22) → BCR-ABL fusion → poor prognosis
T cell ALL is categorized as _____
T cell (it can occur across the board; usually a dominance in “blasts”)
(no distinction that helps in terms of prognosis or tx)
TdT + is an important marker for ______.
lymphoid origin → ALL
(specific to lymphoblasts, negative for AML)
In both T cell and B cell ALL, there is a bone marrow failure which leads to accumulation of ______.
neoplastic (non-functioning) “blasts” in marrow → decreased hematopoiesis