AML with t(7;21)(p22;q22): A new recurrent semi-cryptic RUNX1 rearrangement M. Sales1, N. Foster1, S. Tauro2, J. Cunningham1, N. Pratt1 Departments of Cytogenetics1 and Haematology2 Ninewells Hospital, Dundee ACC Spring Meeting Liverpool 2008

Acute Myeloid Leukaemia (AML) WHO: Clonal expansion of myeloid blasts in bone marrow (BM), peripheral blood (PB) or other tissue More than 20% blasts in BM or PB Can be AML with less than 20% blasts if there is a recognised cytogenetic abnormality e.g. t(8;21), t(15;17) etc Many other cytogenetic abnormalities reported (Karyotyping & FISH)

RAEB Myelodysplastic syndrome (MDS) Refractory anaemia with excess blasts Cytopenias (in PB) 5-9% blasts RAEB-1 10-19% blasts RAEB-2 Unilineage or multilineage dysplasia <1x109/l monocytes RAEB risk of evolution to AML (RAEB-2 = 33%) RAEB-2 median survival 10 months Some RAEB-2 are possibly early stage AML

Patient Information: Clinical 68 year old female GP with fatigue & frequent nail bed infections November 2007 diagnosed with RAEB-2 (17% blasts) and erythroid & megakaryocytic dysplasia Entered into the intensive arm of AML16 trial Randomised to DClo3+5 +Myelotarg (Daunorubicin/Clofarabine/Myelotarg) - 1st induction Cytogenetic remission DClo3+5 (Daunorubicin/Clofarabine) - 2nd induction DA2+5 (Daunorubicin/Cytarabine) - consolidation Azacytidine - maintenance December 2007 remission

Patient Information: Genetics Large number of tetraploid cells Small chromosome 21 investigated by FISH TEL/AML1 extra signal probe (Vysis) Normal TEL (ETV6) & split AML1(RUNX1) signals Reverse DAPI & WCP confirmed chromosome 7 November 2007 Karyotype: 46,XX,t(7;21)(p22;q22)[12]/92,idemx2[21]/46,XX[17] December 2007 complete cytogenetic remission

Diploid Karyotype 46,XX,t(7;21)(p22;q22)

Tetraploid Karyotype 92,XXXX,t(7;21)(p22;q22)x2

TEL/AML1 extra signal probe diploid cell der(21) Normal 21 der(7) Reverse DAPI FISH image

TEL/AML1 extra signal probe tetraploid cell 21 der(21) 21 der(7) der(21) der(7) Reverse DAPI FISH image

WCP7 & TEL/AML1 extra signal probe diploid cell der(7) der(21)

WCP7 & TEL/AML1 extra signal probe tetraploid cell der(7) der(21) der(21) der(7)

Ideograms t(7;21) 7 7 21 21 Hiller B, Bradtke J, Balz H and Rieder H (2004): "CyDAS Online Analysis Site", http://www.cydas.org/OnlineAnalysis/"

Paulsson et al (2006): Patient info 7 yr old boy - Presented March 1995 Pyrexic tonsillitis & cervical adenitis Hypercellular BM Blasts difficult to classify morphologically Immunophenotyping = AML M0 Treatment – initially by NOPHO-AML-93 protocol After induction still 25% blasts 3 additional chemotherapy blocks - CR Allogeneic stem cell transplant (sister) June 1995 Relapse March 2000 – abnormal cytogenetics 2nd CR April 2000 followed by donor lymphocyte infusions Patient still OK April 2005

Paulsson et al (2006): Genetics Apparently normal male at diagnosis Karyotype at relapse 46,XY,t(4;6)(q24;p11),del(5)(q15),t(11;18)(q23;q21)[24] t(7;21)(p22;q22) found while screening paediatric leukaemia's for t(7;21)(q36;p13) Initially detected by WCP for chromosome 7 LSI TEL/AML1 extra signal probe (Vysis) RUNX1 rearranged with USP42 (complex)

Paulsson et al (2006): Findings USP42 – protease in ubiquitin pathway Highly expressed in skeletal muscle, liver & pancreas and weakly in brain, placenta & heart. Also in normal BM and 1o AMLs Fusion protein is thought to have a dominant-negative effect on normal RUNX1 and may retain USP42 protease activity

Conclusion Lack of a visible cytogenetic abnormality does not preclude chimeric genes cryptic rearrangements previously reported in AML MLL/ARHGEF12 - del(11q) MLL/CBL - del(11q) Nup98/NSD1 - t(5;11)(q35;p15.5) Now add t(7;21) to list Others likely – MFISH/SKY & aCGH Larger study required to assess actual frequency and clinical implications (UKCCG coordinated)

AML with t(7;21)(p22;q22): A new recurrent semi-cryptic RUNX1 rearrangement M. Sales1, N. Foster1, S. Tauro2, J. Cunningham1, N. Pratt1 Departments of Cytogenetics1 and Haematology2 Ninewells Hospital, Dundee ACC Spring Meeting Liverpool 2008