MED-341: Acute Leukaemia

Professor Abdulkareem Almomen, MD, FRCPC(March 2011)

– Acute Myeloid Leukemia (AML)

– Acute Lymphoblastic Leukemia (ALL)

– Biphenotypic Acute Leukemia (BAL): My + Ly

Acute Leukaemia: main subtypes

• Clonal expansion of myeloid blasts in blood marrow

(BM), peripheral blood (PB) or other tissue

• Minimum threshold of blast cells for defining AML (BM):– >20% blasts

AML: definition / concept

Proliferation + differentiation block / maturation arrest

Maturation arrest

Maturation arrest

Normal Bone Marrow: Cell Heterogeneity

BM in AML: Monomorphous Cell Appearance

AML5a

AML4-eos

• Incidence: 2 - 3 pts /100.000 inhab - year

• Overall: 1.2% (US)

• Lineal increase with age:

<35: < 1 /100.000 inhab - year >65: >10 /100.000 inhab - year

• Median age: 60 - 70 year-old

• Not apparent increase during last years

AML: epidemiology

• Bone marrow failure – Anemia– Neutropenia– Thrombocytopenia

• Extramedullary involvement (skin, gums, CNS, other)

• Proliferative symptoms

• Coagulopathy

• Leukostasis

• Metabolic disorders (tumor lysis syndrome)

AML: clinical presentation

AML: skin infiltration (granulocytic sarcoma)

AML: gums (gingival) infiltration

Acute Myeloid Leukemia (AML)

• Cytology– PB – BM (BM aspirate ± BM biopsy)

• Cytochemistry– MPO (myeloperoxidase) & Sudan Black B (SBB) – Myeloid origin

– Non-specific esterase (NSE): -naphthyl acetate (ANA), -naphthyl butyrate (ANB) – Monocytic origin

• Inmunophenotype– Hematopoietic precursors: CD34, HLA-DR, CD45– My Ag: CD13, CD33, CD15, MPO, CD117– Megakaryoblastic Ag: CD41, CD61

• Cytogenetics• Molecular biology

– Fusion transcripts (RT-PCR): PML/RAR-, AML1/ETO, CBF-/MYH11, MLL/..., BCR/ABL, DEK/CAN)

– New mutations with prognostic impact: flt-3-ITD, CEBPalfa, NPM, …

AML - diagnosis:

AML – Auer rod

MPO

Naphtol-As-D-acetate esterase -naphthyl acetate esterase

AML : Cytochemistry

CD

56 P

E

100 101 102 103 104

CD2 FITC

10

01

01

10

21

03

10

4

NG

2 P

E

100 101 102 103 104

CD34 FITC

10

01

01

10

21

03

10

4

CD

14 P

E

100 101 102 103 104

CD123 FITC

10

01

01

10

21

03

10

4

AML : Flow cytometry

AML: Cytogenetics

Acute Promyelocytic Leukemia (APL, M3)

bcr1 bcr3

RT-PCR PML/RAR-alpha

FISH: PML/RARA fusion signal

Anti-PGM3 pattern staining

• Minimally differentiated (M0)

• AML w/o maturation (M1)

• AML with maturation (M2)

• Promyelocytic (M3)

• Myelomonocytic (M4)

• Monoblastic (M5a)

• Monocytic (M5b)

• Erythroleukemia (M6)

• Acute megakaryoblastic (M7)  

FAB classification for AML: lineage/differentiation- based

Granulocytic diff

Monocytic diff

I. AML with recurring genetic abnormalities– AML with t(8;21)(q22;q22) & (AML1/ETO) rearrangement– AML with abn BM eosinophils & inv(16)(p13q22)/t(16;16)(p13;q11) -

CBF/MYH11 rearrangement– Acute promyelocytic leukemia associated to t(15;17)(q22;q11-12) &

PML/RAR- rearr– AML with 11q23 (MLL) abn

II. AML with multilineage dysplasia

III. Therapy-related AML

IV. AML not otherwise categorized

WHO, 2001

WHO classification (AML): towards molecularly-based categories

– Favorable: t(15;17), t(8;21), inv(16)

– Intermediate risk: normal karyotype

– Unfavorable: abn 5 (del/-5), abn 7 (del/-7),

inv(3q)/t(3;3), complex karyotype (≥5 abn),

abn 11q, t(6;9), del(17p)

AML: main cytogenetic abnormalities

AML (non-APL): standard approach

Intensification CT Ara-C HD-based

Post-remission tx

AlloSCT AutoSCT CT

Induccion CT

Anthacycline + Ara-C /…

CR~75%

Long-term OS~35-40% (<60)

Salvage therapy

Refractory

Relapse

Acute Lymphoblastic Leukemia (ALL)

ALL: definition

– Clonal expansion of lymphoid (precursor

lymphoid cells) in blood marrow (BM),

peripheral blood (PB) or other tissue

ALL: main subtypes

– B-cell ALL / precursor B lymphoblastic leukemia

– T-cell ALL / precursor T lymphoblastic leukemia

• Incidence: 2/100.000 (inhab-year) • 3/4 in children

• B-ALL: – 80-85%– Predominance in children– 10% presenting without BM involvement (B-cell

lymphoblastic lymphoma)

• T-ALL:– 15% of children ALL– 25% of adult ALL– Predominance in adolescent / young male pts– Frequent presentation with exclusive extramedullary involvement (T-cell

lymphoblastic lymphoma)

ALL: epidemiology

• Extramedullary involvement– CNS– Mediastinal (T-ALL)– Other (lymph node, testicular, ...)

• B symptoms• Bone marrow failure

• Metabolic disorder

ALL: characteristic clinical features

T-ALL: mediastinal involvement

ALL – FAB1 subtype

ALL – FAB2 subtype

Common B-lineage antigens: HLA-DR, CD19, CD79a,CD22

• Pro-B (B-cell progenitor, B-I): Tdt+, CD10(-), cytIg(-), CD20(-)

• Common (early pre-B, B-II): TdT(+), CD10(+), cytIg(-)

• Pre-B (B-III): Tdt(+), cytIg(+)

• Mature B-ALL (B-IV): Tdt(-), sIg+, CD20(+)

B-ALL: immunological classification

T-ALL/Common Ag: Tdt, CD3cyt, CD7

– Early T-ALL: CD1(-),CD2(-),CD3s(-), CD5(-),CD4(-),

CD8(-)

– Thymic T-ALL: CD1a(+),CD2(+),CD5(+)

– Mature T-ALL: CD1a(-), CD2(+),CD5(+),CD3s(+)

T-ALL: immunological classification

– Favorable: t(12;21),

– Intermediate risk: normal karyotype, t(1;19)

– Unfavorable: t(9;22), 11q23 abn [t(4;11) & other],

hypoploid

ALL: main cytogenetic abnormalities

ALL: current therapeutic approach

Consolidation CT

Post-remission

AlloSCT AutoSCT CT (reinduction & maintenance)

CR: 83%

Induction Antr. / VCR / PDN

L-ASA, ARA-C, CFM

Surv*: 80% (children) 35% (adults)

Imatinib: molecular-targeted therapy for Ph-positive ALL

Goldman et al, Lancet 2000

Y = TyrosineP = Phosphate

Bcr-Abl

ATP

Substrate

PPP

P

Abl: a highly overexpressed tyrosine kinase protein in CML & Ph-pos ALL

Imatinib: molecular-targeted therapy for Ph-positive ALL

Goldman et al, Lancet 2000

Bcr-AblBcr-Abl

ATP

Substrate

PPP

P

Imatinib: blocks abl function by interfering with ATP binding

Y = TyrosineP = Phosphate

Outcome

– Response criteria

• Complete response

• Cytogenetics response

• Molecular response

– Failure: primary refractory, relapse

– …

NCI criteria (Cheson et al, 1999)

1. <5% blasts in BM

2. Absence of extramedullary leukemia

3. Recovery of PB counts (ANC >1 & platelet >100x109/L)

4. Minimum 4-week duration

Definition of CR

CR (morphologic assessment) <5% of BM blast cells

Low sensitivity

Universally applicable

Cytogenetic CR Absence of abnormal metaphases

Low sensitivity

Only in cases with cytogenetic abn

(i.e., Ph-pos)

Molecular response Clearance of molecular marker (bcr/abl, PML/RAR, AML1/ETO,...)

Only in AL with known molecular marker

High sensitivity (1 x 10-5)

Response assessment: types (degree) of response

Morphologic assessment of response

CR Non-CR