Presentation on theme: "Traditional Pathology Meets Next-Generation in Acute Myeloid Leukemia"— Presentation transcript:
1 Traditional Pathology Meets Next-Generation in Acute Myeloid Leukemia …and Challenges our Definitionof “Acute” Leukemia !!!PATH 430 Molecular Basis of Disease Michael Rauh, MD, PhD January 19, 2015
2 ObjectivesProvide an overview of acute myeloid leukemia (AML) pathophysiology, current diagnosis, classification, and clinical managementDescribe the emerging role of next-generation sequencing in AML and the detection of occult malignancyProvide a foundation for the discussion of today’s papers:Shlush et al. (Nature, 2014)Jaiswal et al. (NEJM, 2014)
3 The Stem Cell Concept Stem Cells: Capable of self-renewal (although this is a rare event and stem cells are mainly quiescent)Are multipotent (i.e. can give rise to a remarkable number of daughter cells by committing to successive differentiation steps, culminating in terminally-differentiated, mature cells)2-20 celldivisionsper yearDifferentiation
4 Hematopoietic Stem Cells Hematopoietic stem cells (HSC) are found in the bone marrow, cord blood, and in smaller numbers in the peripheral bloodLong-lived cells that give rise to all blood cellsComprise approx. 1 in 10,000 bone marrow cellsIt is estimated that approx. 1,000 to 10,000 HSC contribute to the production of 1011 – 1012 new blood cells throughout the body each day
5 Hematopoiesis The production of mature blood cells by HSC In adults, primarily occurs in the bone marrow
8 HSC mutations increase with age Number of mutationsper HSCIncreasing age of human subjects
9 HSC mutations increase with age Like other cells in our body, HSC have a fidelity rate of about 0.78 × 10−9 mutations per genomic base pair per cell divisionTherefore, mutations randomly appear at a rate of about coding mutations per year of life (i.e. approx. one mutation every 7-8 years)Mutations accumulate with age, and generally do not impact HSC function (i.e. they do not normally cause AML)However, in some people, will these mutations occur in genes that predispose to leukemia?
10 Classification of myeloid disorders (Blast)Bone MarrowFailureTET2,ASXL1BloodCytopenia(s)JAK2JAK2, MPLBCR/ABL, CBLMyeloproliferativeNeoplasmsMyelodysplasticSyndromesAcute MyeloidLeukemiaMPNMDSAMLMature cells↑↓DysplasiararecommonsometimesBlastsNorm (<5%)<5% or 5-19%≥20%AML transformationn/aMutationsTK pathwaysself-renewal, epigenTwo hitsCorey et al. Nature Reviews Cancer 7, 118–129
11 Classification of myeloid disorders Core binding factors,PML-RARA,NPM1, CEBPAFLT3, RASMPNMDSAMLMature cells↑↓DysplasiararecommonsometimesBlastsNorm (<5%)<5% or 5-19%≥20%AML transformationn/aMutationsTK pathwaysself-renewal, epigenTwo hitsCorey et al. Nature Reviews Cancer 7, 118–129
12 AML diagnosis: bone marrow studies BM Aspirate:BM Biopsy:MorphologyImmunohistochemistry
13 AML diagnosis requires ≥ 20% blasts AML: morphologic featuresGranulopoiesisMyeloblastwith Auer RodAML diagnosis requires ≥ 20% blastsin blood or bone marrow
14 AML: French-American-British(FAB) Classification M0: with minimaldifferentiationM1: withoutmaturationM2: with maturationM3: promyelocyticM4: myelomonocyticM5: monoblastic/monocyticM6: erythroidM7: megakaryoblastic
15 AML: flow cytometric analysis Blasts: express CD45 at dim levels on their surface
16 AML: flow cytometric analysis CD34 is a blast marker, but can be expressed by both lymphoid & myeloid blastsMyeloid blasts express other myeloid markers (i.e. CD13, 33, 117), and thishelps to assign their “lineage” and make the diagnosis of AML
21 The t(15;17) translocation also impairs cellular differentiation (i.e. maturation)Maturation Arrest:‘M3’ Acute Promyelocytic Leukemia (APL)
22 APL: using ATRA to induce blast differentiation
23 Are there any other successful targeted aml therapies? No! (not yet…)
24 Standard 3+7 AML “Induction” Chemotherapy An anthracycline, Daunorubicin interacts with DNA by intercalation and inhibition of macromolecular biosynthesis. This inhibits the progression of the enzyme topoisomerase II, which relaxes supercoils in DNA for transcription.3 days, IVCytosine arabinoside (Ara-C) is similar enough to human cytosine deoxyribose (deoxycytidine) to be incorporated into human DNA, but different enough that it kills the cell.Kills dividing cells – not particularly targeted!After induction, if <5% blasts, considered in morphological remission.
25 Putting it all together to arrive at a diagnosis… Morphology, immunophenotyping, chromosomal analysis…Putting it all together to arrive at a diagnosis…
26 AML: Current (2008) Classification WHO M3 Acute myeloid leukemia and related neoplasms:Acute myeloid leukemia with recurrent genetic abnormalitiesAML with t(8;21)(q22;q22); RUNX1-RUNX1T1AML with inv(16)(p13.1q22) or t(16;16)(p13.1;q22); CBFB-MYH11APL with t(15;17)(q22;q12); PML-RARAAML with t(9;11)(p22;q23); MLLT3-MLLAML with t(6;9)(p23;q34); DEK-NUP214AML with inv(3)(q21q26.2) or t(3;3)(q21;q26.2); RPN1-EVI1AML (megakaryoblastic) with t(1;22)(p13;q13); RBM15-MKL1Provisional entity: AML with mutated NPM1Provisional entity: AML with mutated CEBPAAcute myeloid leukemia with myelodysplasia-related changesTherapy-related myeloid neoplasmsAcute myeloid leukemia, not otherwise specifiedAML with minimal differentiationAML without maturationAML with maturationAcute myelomonocytic leukemiaAcute monoblastic/monocytic leukemiaAcute erythroid leukemiaAcute megakaryoblastic leukemiaAcute basophilic leukemiaAcute panmyelosis with myelofibrosisMyeloid sarcomaMyeloid proliferations related to Down syndromeTransient abnormal myelopoiesisMyeloid leukemia associated with Down syndromeBlastic plasmacytoid dendritic cell neoplasmM3Only 2 genemutations!Old FAB:M0M1M2M4M5M6M7
40 SUMMARYCurrently, AML is diagnosed using blast counts, immunophenotyping, chromosomal analysis, and (rarely) mutationsApart from ATRA in t(15;17) AML, treatment is mainly one- size-fits allGene mutation profiling is helping to refine diagnostic risk categories and to guide rational and targeted therapeuticsPaper 1: Mutation profiling unexpectedly reveals evidence of a pre-leukemic statePaper 2: How common is this pre-leukemic state and what are the implications?