title: Low Frequency of ETV6-RUNX1 (t 12; 21) in Saudi Arabian Pediatric Acute Lymphoblastic Leukemia Patients: Association with Clinical Parameters and Early Remission.
abstract: BACKGROUND
  Pediatric acute lymphoblastic leukemia (pALL) patients at King Abdulaziz Medical City represent a pure Saudi Arabian population. ETV6-RUNX1 positive pALL patients have good prognosis as compared to ETV6-RUNX1 negative counterparts. Therefore, frequencies of these two patient groups have a huge consideration in treatment strategies of pALL in a given population. Different geographical locations have been reported to have different frequencies of ETV6-RUNX1 ranging from 10% in Southeast Asia to 30% in Australia.
  
  
  OBJECTIVE
  Therefore, the objective of this study was to establish the ETV6-RUNX1 status of Saudi Arabian pALL patients and its association with clinical parameters and early remission.
  
  
  METHODS
  Clinical parameters and ETV6-RUNX1 status (using FISH technique) of pALL patients attending the Pediatric Oncology Clinic, King Abdulaziz Medical City, Riyadh from 2006 to 2011 were studied. Comparisons between ETV6-RUNX1 positive and negative groups were accomplished using chi-square test or Fisher's exact test. All statistical analyses were performed using SAS version 9.2 (SAS Institute, Inc., Cary, NC).
  
  
  RESULTS
  Out of 54 patients, 33 were male and 21 were females (ratio 1.57:1). B- and T-cell lineages were found in 47 (87%) and 7 (13%) patients respectively. Only 5 (9.3%) patients were ETV6-RUNX1 positive while 49(80.7%) were ETV6-RUNX1 negative. All ETV6-RUNX1 patients (100%) were of B-cell lineage and 80% (4/5) were in the 3-7 year age group. None of the ETV6-RUNX11 patients had ≥ 5% blasts (no remission) at day 14 as compared with 9% in the ETV6-RUNX1 negative group (Figure 1).
  
  
  CONCLUSIONS
  Frequency of ETV6-RUNX1 positive patients (less than 10%) in our pALL patients is much lower than reported for most European countries, North America, Australia and Japan while it is in accordance with ETV6-RUNX1 frequencies from Egypt (11.6%), Pakistan (10%), Spain (2%) and India (5-7%). This shows ethnic differences in genetics of pALL as well as higher frequencies of ETV6-RUNX1 positive pALL mostly in more industrialized countries, probably due to some industrial pollutants or westernized lifestyle.
authors.affiliation: Division of Pediatric Hematology/Oncology Department of Oncology, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, National Guard- Health Affairs, Riyadh, Saudi Arabia E-mail : iqbalz@ksau-hs.edu.sa, drzafarmedgen@yahoo.com.
authors.forename: Khaled
authors.initials: K
authors.lastname: Aljamaan
authors.forename: Talal Khalid
authors.initials: TK
authors.lastname: Aljumah
authors.forename: Saleh
authors.initials: S
authors.lastname: Aloraibi
authors.forename: Muhammad
authors.initials: M
authors.lastname: Absar
authors.forename: Zafar
authors.initials: Z
authors.lastname: Iqbal
mesh_terms: D000293:Adolescent; D001402:B-Lymphocytes / Q000473:pathology; D019070:Cell Lineage / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics*; D005843:Geography; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D011379:Prognosis; D012529:Saudi Arabia; D013601:T-Lymphocytes / Q000473:pathology; D000097764:ETS Translocation Variant 6 Protein
chemical_list: D050676:Core Binding Factor Alpha 2 Subunit; D015514:Oncogene Proteins, Fusion; C102421:TEL-AML1 fusion protein; D000097764:ETS Translocation Variant 6 Protein