title: A formalin-free method for stabilizing cells for nucleic acid amplification, hybridization and next-generation sequencing.
abstract: BACKGROUND
  Formalin has been widely used by pathology laboratories. Its carcinogenicity has led researchers to explore formalin substitutes. Streck Cell Preservative (SCP) is a formalin-free preservative that can preserve cellular antigens. This study was undertaken to investigate the effects of cell preservation using SCP on nucleic acid amplification, hybridization, and next-generation sequencing (NGS) as compared to control frozen cells and cells fixed in the traditional cell and tissue fixative, 10 % neutral buffered formalin (NBF).
  
  
  RESULTS
  The breast cancer cell line, SKBR-3, was used as a model system. Prior to nucleic acid extraction and fluorescence in situ hybridization (FISH), cells were fixed in SCP or NBF overnight at room temperature with frozen cells in parallel. Analysis showed that similar DNA extraction yields and amplification profiles determined by PCR in SCP preserved cells and control frozen cells, whereas NBF preserved cells had decreased DNA yield and impaired PCR amplification. Molecular cytogenetic studies by FISH technique indicated that the ratios of ERBB2 (HER-2/neu) signals to the chromosome 17 centromere (CEP17) were comparable for frozen cells and SCP preserved cells. The fluorescence images of both SCP fixed and control frozen cells were also clear and comparable. On the contrary, the same analysis was unsuccessful with NBF preserved cells due to poor hybridization quality. Our data also demonstrated that SCP had negligible effect on NGS testing.
  
  
  CONCLUSIONS
  We conclude that SCP can be used as an alternative to NBF as a preservative for maintaining the integrity of nucleic acids for nucleic acid amplification, sequencing and FISH analysis.
authors.affiliation: Research and Development Division, Streck, Inc., 109th Street, Omaha, NE, 68128, USA. jqin@streck.com.
authors.forename: Jianbing
authors.initials: J
authors.lastname: Qin
authors.affiliation: Munroe-Meyer Institute for Genetics and Rehabilitation, Cytogenetic and Human Genetics Laboratories, University of Nebraska Medical Center, Omaha, NE 68198, USA. jsanmann@unmc.edu.
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Sanmann
authors.affiliation: Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA. jeff.kittrell@unmc.edu.
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Kittrell
authors.affiliation: Munroe-Meyer Institute for Genetics and Rehabilitation, Cytogenetic and Human Genetics Laboratories, University of Nebraska Medical Center, Omaha, NE 68198, USA. palthof@unmc.edu.
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Althof
authors.affiliation: Munroe-Meyer Institute for Genetics and Rehabilitation, Cytogenetic and Human Genetics Laboratories, University of Nebraska Medical Center, Omaha, NE 68198, USA. ekaspar@unmc.edu.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Kaspar
authors.affiliation: Research and Development Division, Streck, Inc., 109th Street, Omaha, NE, 68128, USA. bhunsley@streck.com.
authors.forename: Bradford A
authors.initials: BA
authors.lastname: Hunsley
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods*; D016707:Tissue Fixation / Q000379:methods*