SM_270b: Acute Lymphoblastic Leukemias Flashcards
Describe hierarchy of hematopoiesis
Hematopoiesis

T cells mature in the ___
T cells mature in the thymus
B cells mature in the ___
B cells mature in the bone marrow
Describe antigen expression in normal B cell development
Antigen expression in normal B cell development

Describe antigen expression in normal T cell development
Antigen expression in normal T cell development

Describe acute lymphoblastic leukemia / lymphoma
Acute lymphoblastic leukemia / lymphoma
- B acute lymphoblastic leukemia / lymphoma: recurrent genetic abnormalities, not otherwise specified
- T acute lymphoblastic leukemia / lymphoma: early precursor T, others

LBL involves ____, while ALL involves ____
LBL involves mass lesion and <25% blasts in bone marrow, while ALL involves > 25% blasts in bone marrow

Describe epidemiology of ALL
Epidemiology of ALL
- Most common cancer of children
- 85% of ALL are B-ALL
- Peak incidence of T-ALL/LBL in adolescence
- Male predominance
ALL is associated with ___
ALL is associated with Down syndrome

Describe B-ALL pathophysiology
B-ALL pathophysiology
- Acquired genetic alterations
- Maturation arrest and cell proliferation
- Bone marrow replaced by neoplastic lymphoblasts and normal hematopoiesis impaired
- Peripheral cytopenia
- Lymphoblasts enter blood and infiltrate other organs (spleen, lymph nodes)
Describe B-ALL clinical features
B-ALL clinical features
- Abrupt onset within days to a few weeks
- Symptoms related to bone marrow failure: anemia, thrombocytopenia, neutropenia
- B symptoms: fever, night sweats
- Hepatosplentomegaly, lymphadenopathy, testicular enlargement
- Bone pain
- Uncommon CNS involvement
Describe T-ALL / LBL clinical features
T-ALL / LBL clinical features
- High WBC count
- Anterior mediastinal mass
- SVC syndrome: pain, dysphagia, dyspnea, or swelling of neck / face / upper limbs due to obstruction of SVC
- Tracheal obstruction
- Pericardial and pleural effusion
- CNS involvement

This is a ___ seen in ___

Lymphoblast in ALL

This is ___ seen in ___

Hand-mirror cell in ALL

Describe ALL morphology
ALL morphology
- Bone marrow biopsy: hypercellular, sheets of blasts
- Bone marrow aspirate: increased number of blasts
- B and T lymphoblasts are morphologically similar

TdT, CD19, and cytoplasmic D3 are markers of ___
TdT, CD19, and cytoplasmic D3 are markers of ALL
Describe important phenotypic markers of ALL
ALL important phenotypic markers
- Precursor markers: TdT, CD34, CD1a (T cells)
- B cell markers: CD19, CD10, CD22
- T cell markers: cytoplasmic CD3, CD1a, CD2, CD5, CD7, CD4 and/or CD8

Describe ALL genetics
ALL genetics
- Most cases of ALL have cytogenetic (chromosomal) abnormalities
- Some recurrent genetic abnormalities define specific subtypes of B-ALL

___ typically occurs in infants with ALL
KMT2A/MLL translocations t(v;11) typically occurs in infants with ALL
___ typically occurs in children with ALL
t(12;21) ETV6-RUNX1 typically occurs in children with ALL
____ typically occurs in adults with ALL
t(9;22) BCR-ABL1 Philadelphia chromosome typically occurs in adults with ALL
Describe B-ALL with t(12;21)
B-ALL with t(12;21)
- Fusion of ETV6 with RUNX1 gene
- Most common genetic lesion in children with B-ALL: 25%
- Favorable prognosis

Describe B-ALL with t(9;22) or Ph+ B-ALL
B-ALL with t(9;22) or Ph+ B-ALL
- BCR-ABL1 fusion gene
- 25% of adults
- Poor prognosis: Ph+ has poor prognosis, imatinib improves prognosis
- Treatment with tyrosine kinase inhibitors

Describe B-ALL with t(v;11q23) KMT2A rearranged
B-ALL with t(v;11q23) KMT2A rearranged
- Occurs mostly in infants t(14;11)
- 60-80% of infants with ALL have translocations involving 11q23.3
- High WBC counts, organomegaly, CNS involvement
- Poor prognosis
Describe T-ALL genetics
T-ALL genetics
- Abnormal karyotypes in 50-70% cases
- No major impact on prognosis
- Most common recurrent cytogenetic abnormalities involves TCR loci (14q, 7p)
- 50% of cases have NOTCH1 mutations
Describe early T-cell precursor ALL
Early T-cell precursor ALL
- Defined by early T cell precursor phenotype
- Low CD5, no CD1a or CD8
- Express CD34
- Express myeloid antigens (no MPO)
- High risk
Survival for children with ALL has ___ over time
Survival for children with ALL has improved over time
Describe prognosis of ALL
ALL prognosis
- Age at presentation: age < 1 is unfavorable
- Initial WBC: unfavorable if > 100,000
- Cytogenetics
- Favorable: t(12;21), hyperdiploidy
- Unfavorable: MLL / KMT2A gene, t(9;22) / BCR-ABL1, low hyodiploidy
- Time to response to inducation chemo: slow response is unfavorable
- CNS / testicular involvement at initial diagnosis is unfavorable
Blinatumomab ____
Blinatumomab simultaneously binds to specific molecules on B-ALL cells and T cells, bringing T cells close enough to ALL cells to recognize and kill them
This is ___
___ would be a good prognosis

B-lymphoblastic leukemia
t(12;21) would be a good prognosis

This is ___
Phenotype of abnormal cells is ___

T-lymphoblastic leukemia
Phenotype of abnormal cells is cytoCD3+, Tdt+, CD19-, ctoCD22-
