title: Genetic evaluation of mesenchymal stem cells by G-banded karyotyping in a Cell Technology Center.
abstract: OBJECTIVE
  To present the initial results of first three years of implementation of a genetic evaluation test for bone marrow-derived mesenchymal stem cells in a Cell Technology Center.
  
  
  METHODS
  A retrospective study was carried out of 21 candidates for cell therapy. After the isolation of bone marrow mononuclear cells by density gradient, mesenchymal stem cells were cultivated and expanded at least until the second passage. Cytogenetic analyses were performed before and after cell expansion (62 samples) using G-banded karyotyping.
  
  
  RESULTS
  All the samples analyzed, before and after cell expansion, had normal karyotypes, showing no clonal chromosomal changes. Signs of chromosomal instability were observed in 11 out of 21 patients (52%). From a total of 910 analyzed metaphases, five chromatid gaps, six chromatid breaks and 14 tetraploid cells were detected giving as total of 25 metaphases with chromosome damage (2.75%).
  
  
  CONCLUSIONS
  The absence of clonal chromosomal aberrations in our results for G-banded karyotyping shows the maintenance of chromosomal stability of bone marrow-derived mesenchymal stem cells until the second passage; however, signs of chromosomal instability such as chromatid gaps, chromosome breaks and tetraploidy indicate that the long-term cultivation of these cells can provide an intermediate step for tumorigenesis.
authors.affiliation: Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brazil. Electronic address: tamaraborgonovo@yahoo.com.br.
authors.forename: Tamara
authors.initials: T
authors.lastname: Borgonovo
authors.affiliation: Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brazil.
authors.forename: Isadora May
authors.initials: IM
authors.lastname: Vaz
authors.affiliation: Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brazil.
authors.forename: Alexandra Cristina
authors.initials: AC
authors.lastname: Senegaglia
authors.affiliation: Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brazil.
authors.forename: Carmen Lucia Kuniyoshi
authors.initials: CL
authors.lastname: Rebelatto
authors.affiliation: Pontifícia Universidade Católica do Paraná (PUC-PR), Curitiba, PR, Brazil.
authors.forename: Paulo Roberto Slud
authors.initials: PR
authors.lastname: Brofman
keywords: Chromosomal instability; Cytogenetics; Mesenchymal stromal cells