Intrachromosomal amplification of chromosome 21 (iAMP21) detected by\nETV6/RUNX1 FISH screening in childhood acute lymphoblastic leukemia: a case\nreport
An 11-year-old girl with a two-month history of joint pain in both hands and shoulders\nthat evolved to arthritis was admitted to the Onco-Hematology Pediatric Service of\nHospital Estadual Bauru, São Paulo, Brazil. A physical examination revealed that the\npatient did not present enlarged palpable lymph nodes in the cervical, submandibular,\naxillary or inguinal regions. No signs of musculoskeletal abnormalities, including\ninflammatory joint arthritic changes, were noted. Examinations of the cardiovascular and\nrespiratory systems were also normal. The hemoglobin level was low (11 g/dL), white\nblood cell count was also low (3 x 109/L) with no blast cells, platelet count\nwas 165 x 109/L and lactate dehydrogenase (LDH) was 23 U/L. The morphologic\nevaluation of the bone marrow showed 95% blast cells with lymphoid characteristics\ncompatible with French-American-British (FAB) classification L1. Flow cytometry revealed\na population with 71% of blast cells that expressed CD79a, CD19, CD20, CD38, CD58, CD66c\nheterogeneously, low expressions for CD10, CD13, CD22, and negative expressions for\ncCD3, sCD3, cCD7, CD45, CD34, CD15, CD33, cIgM, and myeloperoxidase (MPO) thus\ncompatible with BCP-ALL. The patient was initially treated according to the\nALL-IC-BFM2009 protocol for medium risk(. Peripheral blood showed good treatment response to prednisone on\nDay 8, and bone marrow examination at the end of the induction therapy showed complete\nremission. The patient is clinically well without any evidence of disease five months\nafter diagnosis.\nThe patient's bone marrow sample was sent for cytogenetic analysis, at the time of\ndiagnosis, to the Cytogenetics Laboratory of the Bone Marrow Unit, National Cancer\nInstitute (INCA). The 24-hour culture technique was unsuccessful in obtaining metaphase\ncells for chromosome analysis(.\nFluorescence in situ hybridization (FISH) was performed on interphase cells using the\ncommercially available LSI ETV6/RUNX1 ES dual color translocation probe, LSI MLL dual\ncolor break apart rearrangement probe, and the LSI BCR/ABL ES dual color translocation\nprobe (All from Abbott Diagnostics, Maidenhead, United Kingdom), according to the\nmanufacturer's instructions. Two-hundred interphase cells were scored for each probe.\nInterphase FISH (iFISH) analysis revealed no ETV6/RUNX1 fusion signals and 6 to 10\nsignals for the RUNX1 probe in 75% of the analyzed nuclei in this child ( & ). FISH analyses with MLL and BCR/ABL probes showed normal results.