Acute Lymphocytic Leukemia ALL

Classification

• Morphology: no granules (granules seen in myeloid lineage)

• Cytochemistry: • terminal deoxynudeotidyl transferase (TdT) in 95% of ALL

• Cytogenetics: t(9;22) Philadelphia chromosome (Ph) in 25% of adults w ALL

• Immunohistochemistry distinguishes 3 major phenotypes (Burkitt's usually treated differently)

WHO Immunophenotype

Classification of ALL

WHO Type

FAB

Adult Freq

Immunohistochemistry

Precursor B-cell

L1.L2

75%

- TdT. • CD19; variable CD10.CD20

Precursor T-cell

L1.L2

20%

TdT, T-cell Ag (CD2.3.5.7) CD10. mature T-cell Ag (CD4,8)

B-cell

L3

5%

© TdT, © surface Ig

Treatment (HE/M 2006;3S4166)

• Induction chemo: combination of cyclophosphamide, doxorubicin, vincristine.

methotrexate, steroids. ± asparaginase

• CNS prophylaxis: intrathecal MTX cytarabine either cranial irradiation or systemic

• Postremission therapy options:

consolidation intensification chemo followed by maintenance chemo high-dose chemo w alio or auto HSCT; survival benefit in high-risk pts w alio HSCT

• Ph • t(9;22) • add imatinib & consider for allogeneic HSCT

• MLL-AF4 t(4:11) - consider for allogeneic HSCT

Prognosis

• Cure achieved in 50-70% if good prog, factors vs. in 10-30% w poor prog, factors

• Good prognostic factors: younger age.WBC 30.000 p.l. T-cell immunophenotype.

absence of Ph chromosome or t(4;11). early attainment of CR

• Gene expression patterns may be useful in predicting chemo resistance (nqm roosts*»

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