Detection of RUNX1-RUNX1T1 Fusion Gene in AML Patients by FISH Technique in Iraq

Abstract

Background: AML with t(8;21)(q22;q22.1) is a balanced translocation that results in the fusion of RUNX1 and RUNX1T1. The translocation product is located on derivative chromosome 8. It has characteristic morphologic and immunophenotypic features and is linked with good prognosis. t(8;21)(q22;q22.1) AML is diagnostic of AML regardless of blast count. Objectives: To detect the RUNX1-RUNX1T1 fusion gene) in patients with AML by FISH technique and to investigate the relation between this chromosomal abnormality and the immunophenotypic markers CD117, cMPO, CD34, CD13, CD64 and CD33, clinical features and haematological parameters (Hb, WBC, blast percentage and platelets). Materials ad Methods: Fifty patients with de novo AML were selected sequentially from Baghdad teaching hospital in medical city from June 2020 till April 2021. History was taken and data were collected for each patient using a questionnaire form that included: name, age, sex, symptoms and physical signs. The data of haematological parameters and CD markers expression were collected from the patients’ diagnostic reports. Results:The RUNX1/RUNX1T1 fusion gene expression was positive in 4 patients representing 8% whereas 46 patients representing 92% of the samples had negative gene expression. Among the 4 positive AML patients for RUNX1/RUNX1T1 fusion gene expression, M2FAB subtype was revealed in all the cases. All the positive cases expressed CD117 and CD34 markers, while it was noted that 3 out of 4 positive cases were having cMPO and CD13 markers and one positive case expressed CD33 and CD64. Conclusion: It’s shown that RUNX1-RUNX1T1 fusion gene frequency in AML Iraqi patients is similar to international reports.