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16 Cards in this Set
- Front
- Back
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What are acute lymphoblastic leukemia\lymphomas? |
ALLs are neoplasms composed of immature B or T cells which are referred to as lymphoblasts. . |
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What ALL manifests as childhood acute leukemia? |
B-ALL |
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What form of ALL is less common, how and in whom it tend to present? |
T-ALL, in adolescent males as thymic "lymphomas". |
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What lymphoma is the most common cancer in children? |
ALL |
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What age is the peak for B-ALL? |
3 |
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What is the peak age of T-ALL? |
Adolescence- the age when the thymus reaches the maximum size. |
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T-ALL, what gene have gain of function mutation in up to 70%? |
NOTCH1 |
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What loss of function mutation there are in B-ALL? |
PAX5, E2A, Balanced 12;21 involving the genes ETV6 and RUNX1. |
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What is the pathogenesis behind ALLs? |
Dysregulations the expression and function of transcription factors required for normal development of B and T cells. The disturbednes of differentiation of lymphoid precursors promote maturation arrest> increase self renewal , a stem cell like phenotype. |
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How many mutations are sufficient to produce full blown ALL? |
Fewer than 10. |
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What are the characteristic features of the tumor cells in ALLs? |
Scant basophilic cytoplasm and nuclei somewaht larger than those of small lymphocytes. Nucleoli are usually small and often demarcated by rim of condensed chromatin. Mitotic rate is high. |
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What are the difference between myeloblasts and lymphobasts? |
Lymphoblasts have more condensed chromatin Less conspicuous nucleoli Smaller amounts of cytoplasm that usually lacks granules. |
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What are the histochemical differences between myeloblasts and lymphoblasts? |
Lymphoblasts are negative for myeloperoxidase Contain periodic acid Shiff-positive material. |
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What is the immunophenotype of ALLs? |
TdT-expressed only in pre-B and pre-T lymphoblasts. |
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What factors are associated with a worse prognosis of ALL? |
1. Age younger than 2 2. Presentation in adolescence or adulthood 3. Peripheral blood blast > 100,000 |
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What are the factors that are associated with favorable prognosis in ALL? |
1. Age between 2-10 2. Low white cell count 3. Hyperdiploidy 4. Trisomy of chromosomes 4,7,10 5.Presence of 12;21. |
