title: Monoallelic and biallelic deletions of 13q14 in a group of CLL/SLL patients investigated by CGH Haematological Cancer and SNP array (8x60K).
abstract: BACKGROUND
  Deletion of 13q14 is the most common cytogenetic change in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and is detected in about 50 % of patients by fluorescence in situ hybridization (FISH), which can reveal presence of del(13)(q14) and mono- or biallelic deletion status without information about the size of the lost region. Array-comparative genomic hybridization (aCGH) and single nucleotide polymorphism (SNP) can detect submicroscopic copy number changes, loss of heterozygosity (LOH) and uniparental disomy (UPD) regions. The purpose of this study was detection of the size of del(13)(q14) deletion in our group of patients, comparing the size of the monoallelic and biallelic deletions, detection of LOH and UPD regions.
  
  
  RESULTS
  We have investigated 40 CLL/SLL patients by karyotype, FISH and CGH and SNP array. Mutational status was of immunoglobulin heavy-chain variable-region (IGVH) was also examined. The size of deletion ranged from 348,12 Kb to 38.97 Mb. Detected minimal deleted region comprised genes: TRIM13, miR-3613, KCNRG, DLEU2, miR-16-1, miR-15a, DLEU1. The RB1 deletions were detected in 41 % of cases. The average size in monoallelic 13q14 deletion group was 7,2 Mb while in biallelic group was 4,8 Mb. In two cases 13q14 deletions were located in the bigger UPD regions.
  
  
  CONCLUSIONS
  Our results indicate that bigger deletion including RB1 or presence of biallelic 13q14 deletion is not sufficient to be considered as adverse prognostic factor in CLL/SLL. CytoSure Haematological Cancer and SNP array (8x60k) can precisely detect recurrent copy number changes with known prognostic significance in CLL/SLL as well as other chromosomal imbalances. The big advantage of this array is simultaneous detection of LOH and UPD regions during the same test.
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland ; Department of Pathology and Laboratory Diagnostics, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, 15B Wawelska Str, 02-034, Warsaw, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Grygalewicz
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Woroniecka
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Rygier
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Klaudia
authors.initials: K
authors.lastname: Borkowska
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Rzepecka
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Martyna
authors.initials: M
authors.lastname: Łukasik
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Budziłowska
authors.affiliation: Flow Cytometry Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Rymkiewicz
authors.affiliation: Flow Cytometry Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Błachnio
authors.affiliation: Department of Medical Genetics, Mother and Child Institute, Warsaw, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Nowakowska
authors.affiliation: Department of Medical Genetics, Mother and Child Institute, Warsaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Bartnik
authors.affiliation: Department of Medical Genetics, Mother and Child Institute, Warsaw, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Gos
authors.affiliation: Cancer Genetic Laboratory, Pathology and Laboratory Diagnostics Department, Centre of Oncology, M. Skłodowska-Curie Memorial Institute, Warsaw, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Pieńkowska-Grela
keywords: 13q14 deletion; CGH and SNP array; CLL/SLL; UPD