RT Journal Article ID 45e22ab5768dbd48 A1 Chandran, Ramachandran Krishna A1 Geetha, Narayanan A1 Sakthivel , Kunnathur Murugesan A1 Aswathy, Chandran Geetha A1 Gopinath, Preethi A1 Nair, Jagathnath Krishna Kumarapillai Mohanan A1 Sreedharan, Hariharan T1 Prognostic Implications of Derivative Chromosome 9 Deletions in Patients with Advanced-Stage Chronic Myelogenous Leukemia JF Journal of Environmental Pathology, Toxicology and Oncology JO JEP(T) YR 2018 FD 2018-04-19 VO 37 IS 2 SP 117 OP 126 K1 chronic myelogenous leukemia K1 atypical BCR/ABL1 gene rearrangements K1 derivative chromosome 9 deletion K1 fluorescence in situ hybridization AB Elucidation of cryptic BCR/ABL1 gene rearrangement is exceptionally important in the clinical diagnosis and prognosis of chronic myelogenous leukemia (CML). Previous reports indicated an adverse prognostic effect of atypical BCR/ABL1 gene rearrangements with submicroscopic ABL1-BCR deletions on derivative chromosome 9 [der(9)] in CML patients. Dual color dual fusion locus-specific BCR/ABL1 fluorescent in situ hybridization (FISH) analysis together with G-banding using trypsin and Giemsa (GTG banding) was performed in 489 patients at different stages of CML to investigate the spectrum of BCR/ABL1 gene rearrangements. Among the study group analyzed, a significantly higher frequency of BCR/ABL1 gene rearrangements that is consistent with der(9) deletion were observed in the blast crisis (BC) phase at 41.67%, followed by the accelerated phase (AP) at 36.84%, the imatinib mesylate (IM)-resistant chronic phase (CP) at 23.08%, and the lowest incidence was found in de novo CP at 16.61%. 1R1G1F (1 red, 1 green, 1 fusion) with concurrent loss of ABL1-BCR fusion gene on der(9) chromosome was the major signal pattern identified in each group. The results from the current study show that this unusual BCR/ABL1 gene rearrangement is one of the steering forces toward disease progression in CML. Patients in AP/BC of CML with der(9) deletion showed poor response to IM therapy; however, patients with der(9) deletion in the early phases of CML responded well to IM treatment. Therefore, the establishment of an atypical FISH signal pattern in CML is of paramount important because it is associated with adverse clinical prognostic implications in advanced stages of the disease. PB Begell House LK https://www.dl.begellhouse.com/journals/0ff459a57a4c08d0,000ba8935c78b811,45e22ab5768dbd48.html