1. SH/EAHP Workshop 2013 Case 93 Winnie Wu, M.D. Sheeja Pullarkat, M.D.

2. Clinical History 66 yo M with history of coronary artery disease presented with 6 weeks of fatigue & flu-like symptoms 66 yo M with history of coronary artery disease presented with 6 weeks of fatigue & flu-like symptoms  WBC: 34.9 x 10 9 /L  30% blasts  23% PMNs  18% bands  24% lymphocytes  4% eosinophils  1% basophils  Hgb: 12.1 g/dl  Plt: 199 x 10 9 /L

3. Peripheral blood 1000x

4. Peripheral blood 1000x

5. BM Touch prep 1000x

6. BM biopsy 1000x

7. Flow Cytometry: BM Blasts, 77%  Positive:  CD34 (subset)  CD117 (subset)  CD13  CD15 (subset)  CD33  CD16 (subset)  CD11b (subset)  CD36 (subset)  CD71 (dim)  HLA-DR (subset)  CD38 (subset)  Aberrant CD7  Negative: intracellular myeloperoxidase

8. 46,XY,t(4;12)(q12;p13)[8]/ 46,idem,del(5)(q22q35)[12]

9. SCFD2-LNX- PDGFRA tri-color break-apart FISH probe for 4q12 (Abbott Molecular-Vysis)

10. SCFD2-LNX- PDGFRA tri-color Break-apart FISH probe for 4q12: PDGFRα rearrangement

11. ETV6 dual-color break-apart probe for 12p13 (Abbott Molecular-Vysis)

12. ETV6 dual-color Break-apart probe for 12p13: ETV6 rearrangement

13. Initial Proposed Diagnosis Acute myeloid leukemia with t(4;12)(q12;p13); ETV6-PDGFRA

14. AML with t(4;12)(q12;p13) ~ 20 reported cases ~ 20 reported cases 1) Background of multilineage dysplasia 2) Blasts morphologically resemble prolymphocytes

15. AML with t(4;12)(q12;p13) 3) An immature immunophenotype CD7+/CD34+/CD117+/CD13+/ HLA-DR+ CD7+/CD34+/CD117+/CD13+/ HLA-DR+ Absent or low MPO Absent or low MPO 4) Peripheral blood and marrow basophilia

16. AML with t(4;12)(q12;p13): Prognosis Poor prognosis Poor prognosis Median overall survival, 8 months (n = 15 patients) Median overall survival, 8 months (n = 15 patients)

17. Imatinib in AML with t(4;12)(q11-q21;p13) Limited experience; anecdotal evidence suggests refractoriness to tyrosine kinase inhibitors Limited experience; anecdotal evidence suggests refractoriness to tyrosine kinase inhibitors Current case: Patient failed induction chemotherapy & imatinib Current case: Patient failed induction chemotherapy & imatinib Patient eventually achieved morphologic but not cytogenetic remission Patient eventually achieved morphologic but not cytogenetic remission Patient died from infectious complications 14 months following allogeneic stem cell transplant Patient died from infectious complications 14 months following allogeneic stem cell transplant

18. Requests for Discussion from Panel Differences between this case and cases of myeloid and lymphoid neoplasm with eosinophilia with PDGFRA-FIP1L1 Differences between this case and cases of myeloid and lymphoid neoplasm with eosinophilia with PDGFRA-FIP1L1 What may be the role of 5q31 deletion? Is this responsible for the multilineage dysplasia observed in this case? Did the cases of AML with t(4;12) in the literature had this/other associated abnormality? What may be the role of 5q31 deletion? Is this responsible for the multilineage dysplasia observed in this case? Did the cases of AML with t(4;12) in the literature had this/other associated abnormality?

19. Myeloid & Lymphoid Neoplasms with PDGFRA- FIP1L1 AML with t(4;12)(q11- q13;p13) No dysplasiaMultilineage dysplasia EosinophiliaBasophilia Morphologic features of CEL +/- blasts +/- mast cells Prolymphocyte-like blasts CD7+, MPO- Response to imatinibPoor response to imatinib Good prognosisPoor prognosis

20. Cools J, Blood 1999; 94: 1820-4. with similar features to those here Four cases of AML with t(4;12)(q11- q12;p13) with similar features to those here ETV6 gene was fused with the BTL (aka CHIC2) gene RT-PCR demonstrated that the ETV6 gene was fused with the BTL (aka CHIC2) gene Generating a Generating a 5’-CHIC2/ETV6-3’ fusion transcript which is transcribed from the CHIC2 promoter

21. PDGFRA as an Innocent Bystander While PDGFRA is most certainly rearranged, it does not contain the translocation breakpoint Moreover, PDGFRA would be located at the 5' end of the 5’-CHIC2-ETV6-3’ fusion transcript so most likely the tyrosine kinase is not upregulated This may explain why these cases are unresponsive to imatinib In the absence of molecular characterization, one cannot reliably distinguish between ETV6- PDGFRA fusion & CHIC2-ETV6 fusion

22. CHIC2/ETV6 vs ETV6/PDGFRA Only 1 case of ETV6-PDGFRA has been described: MPN with eosinophilia Only 1 case of ETV6-PDGFRA has been described: MPN with eosinophilia Imatinib led to clinical & hematologic resolution & cytogenetic remission Imatinib led to clinical & hematologic resolution & cytogenetic remission Curtis et al. Br J Haematol. 2007

23. Request for Discussion from Panel Differences between this case and cases of myeloid and lymphoid neoplasm with eosinophilia with PDGFRA-FIP1L1 Differences between this case and cases of myeloid and lymphoid neoplasm with eosinophilia with PDGFRA-FIP1L1 What may be the role of 5q31 deletion? Is this responsible for the multilineage dysplasia observed in this case? Did the cases of AML with t(4;12) in the literature had this/other associated abnormality? What may be the role of 5q31 deletion? Is this responsible for the multilineage dysplasia observed in this case? Did the cases of AML with t(4;12) in the literature had this/other associated abnormality?

24. Dysplasia & del 5q Majority of demonstrated multilineage dysplasia even in absence of del 5q or other MDS cytogenetics Majority of AML with t(4;12)(q11-q21;p13) demonstrated multilineage dysplasia even in absence of del 5q or other MDS cytogenetics Only 2 other cases in literature demonstrated concurrent t(4;12)(q12;p13) & del 5q Only 2 other cases in literature demonstrated concurrent t(4;12)(q12;p13) & del 5q In all cases, t(4;12) was in stemline & del 5q was in sideline & likely represents clonal evolution In all cases, t(4;12) was in stemline & del 5q was in sideline & likely represents clonal evolution Refractory to therapy Refractory to therapy

25. Conclusions AML with t(4;12)(q12;p13) has characteristic pathologic & prognostic features AML with t(4;12)(q12;p13) has characteristic pathologic & prognostic features We favor that AML with t(4;12)(q12;p13) leads to CHIC2-ETV6, detectable only by molecular methods We favor that AML with t(4;12)(q12;p13) leads to CHIC2-ETV6, detectable only by molecular methods ETV6-PDGFRA cannot be excluded ETV6-PDGFRA cannot be excluded

26. Conclusions Important to differentiate AML with t(4;12)(q12;p13) CHIC2/ETV6 from myeloid/lymphoid neoplasms with PDGFRA rearrangement due to the drastically different pathologic, therapeutic & prognostic implications Important to differentiate AML with t(4;12)(q12;p13) CHIC2/ETV6 from myeloid/lymphoid neoplasms with PDGFRA rearrangement due to the drastically different pathologic, therapeutic & prognostic implications AML with t(4;12)(q12;p13) and CHIC2- ETV6 is refractory to TKI ETV6-PDGFRA may be sensitive to TKI

27. Final Proposed Diagnosis Acute myeloid leukemia with t(4;12)(q12;p13); possible CHIC2-ETV6 Consensus Diagnosis Acute myeloid leukemia with t(4;12)(q12;p13); CHIC2-ETV6 vs ETV6-PDGFRA