title: Association between sister chromatid exchange and double minute chromosomes in human tumor cells.
abstract: BACKGROUND
  Double minute chromosomes (DMs) are the cytogenetic hallmark of extra-chromosomal genomic amplification. They can well represent the advanced stage of malignancy. However, the mechanisms of DM generation are still not fully understood. Here, the sister chromatid exchange (SCE) was used to determine whether the occurrence of DMs was related to the high genomic instability in human carcinoma cells. We analyzed SCE frequencies in two groups of cell lines: the first group contained DM-positive cell lines such as UACC-1598, SK-PN-DW, and NCI-N87 carcinomas, while the second group comprised DM-negative cell lines including HO-8910, U251, and MGC-803.
  
  
  RESULTS
  The data showed that SCE was significantly increased in the DM-positive cells as compared to the DM-negative cells. In addition, there was a positive correlation between the incidence of DMs and the SCE frequency in the UACC-1598, SK-PN-DW, and NCI-N87 carcinoma cells.
  
  
  CONCLUSIONS
  Because SCE can reflect general genome instability, it is suggested that the DMs are likely to be closely associated with genomic instability in carcinoma cells. Meanwhile, SCE may be involved in the malignant progression of DM-positive cancers.
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Xiangning
authors.initials: X
authors.lastname: Meng
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Bai
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.|Key Laboratory of Medical Genetics, Heilongjiang Higher Education Institutions, Harbin Medical University, Harbin, China.
authors.forename: Songbin
authors.initials: S
authors.lastname: Fu
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Rongwei
authors.initials: R
authors.lastname: Guan
authors.affiliation: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Sun
keywords: Double minute chromosomes; Double-strand DNA break; Sister chromatid exchange