Discovery of Mutated ZNF208 Gene As a Novel Transcription Factor Exclusively Associated with Accelerated Phase and Blast Crisis Chronic Myeloid Leukemia: Hunt for Common Biomarker of Fatal CML Progression

Abstract

Other Authors and their Affiliations: Muhammad Absar8, Tanveer Akhtar8, Masood Shammas9, Salman Basit10, Aamer Aleem11, Amer Mahmood11 1College of Applied Medical Sciences (CoAMS-A), King Saud Bin Abdulaziz University for Health Sciences / KAIMRC/ SSBMT, Al-Ahsa, Saudi Arabia; 8Hematology, Oncology and Pharmaco-genetic Engineering Sciences (HOPES) Group, Health Sciences Laboratories (HaSiL), Department of Zoology, Faculty of Biological Sciences, University of the Punajb, Lahore, Pakistan; 9Dana Farbar Cancer Institute, University of Harvard , Boston , United States of America; 10Centre for Genetics and Inherited Diseases, Taibah University, Madinah; 11College of Medicine, King Saud University, Riyadh, Saudi Arabia. #Corresponding author: Dr. Zafar Iqbal, drzafar.medgen1@gmail.com; iqbalz@ksau-hs.edu.sa Introduction: Chronic Myeloid Leukemia (CML) primarily develops as a result of t(22;9) that creates Philadelphia chromosome and oncogenic BCR-ABL fusion transcript (1). Discovery of BCR-ABL paved the way for designing signal transduction inhibitor drugs called tyrosine kinase inhibitors (TKIs) that have revolutionized CML treatment in 21st century, by making survival of CML equal to general population (2). Nevertheless, TKIs are minimally effective CML patients progressed to blast crisis (BC-CML). Unfortunately mechanism of CML progression is poorly understood (2). Various transcription factors (TFs) are associated with different diseases and progression of many cancers (3). Although a large number of TFs are involved in pathogenesis of acute leukemias, very little is known about role of TFs in CML progression. Therefore, objective of this study was to find about novel TFs associated with CML progression. Materials and Methods: Patient selection: The study subjects included accelerated phase (AP-CML) and blast crisis phase CML (BC-CML) patients (Experimental groups 1 & 2, respectively) while chronic phase treatment-naïve CML patients (CP-CML) were used as control 1, CP-CML CML long-term TKI responders (at least 3 continuous years of MMR) as control group 2 and TK-resistant CML patients as control group 3, along with healthy controls. Sample collection: DNA extraction and Clinical follow-up: 10 ml peripheral blood was collected from all study subjects. DNA was extracted and patient follow-up was carried out during course of this study. All treatment criteria per ENL guidelines were adopted. Whole Exome Sequencing (WES): WES was carried out using Illumina NGS instrument (HiSeq). bcl files were converted to fastq files by using bcl2fastqtool (4). Raw reads were aligned to genome using BWA tools while whole exome variants were annotated using Illumina Variant Studio (4). R package was employed to align specific TF-gene mutants to disease phenotypes (5). TF-genes mutated in all AP/BC-CML patients but not mutated in any of control groups were selected. Variants were confirmed using Sanger sequencing. Results: We found ZNF208 as a novel TF-gene mutated in all AP/BC-CML but in none of the controls (missense mutations G64A). It shows that mutated ZNF208 is a novel biomarker exclusively for advanced phases of CML. Discussion: ZNF208, a member of zing-finger binding transcription factor family, has been reported to be play role as tumor suppressor gene in various cancers through distant signaling pathways (3,6,7). Further studies are required to find exact role of ZNF208 in CML progression and its evaluation as potential biomarker and novel drug target in AP- and BC-CML. Conflict of interest: The authors declare that they have no conflict of interests.