title: DNA extraction from formalin-fixed laryngeal biopsies: Comparison of techniques.
abstract: CONCLUSIONS
  PCR-quality DNA could be extracted from formalin-fixed paraffin-embedded (FFPE) samples with amplicons of at least 390 bp. Paraffin removal was not a necessary step. Proteinase K digestion was as efficient as the commercial kit for DNA extraction with a lower cost.
  
  
  OBJECTIVE
  To compare different DNA extraction protocols for FFPE samples and to describe the suitability of the extracted DNA for PCR reactions.
  
  
  METHODS
  For deparaffinization the following techniques were compared: alkaline heat, xylene, and no removal. For DNA extraction, proteinase K digestion and organic extraction were compared. A commercial extraction kit was included as standard. DNA quality was assessed by PCR amplification of the HFE gene, for amplicons of 208 and 390 bp.
  
  
  RESULTS
  Extraction with the commercial kit and proteinase K digestion were more efficient than other techniques, with no statistical difference between them for both amplicons. The proteinase K digestion buffer had a cost of U$ 0.2 per sample and the commercial kit of U$7 per sample.
authors.affiliation: Departamento de Otorrinolaringología, Hospital San Juan de Dios, Facultad de Medicina, Universidad de Chile, Santiago, Chile. mtorrente@med.uchile.cl
authors.forename: Mariela C
authors.initials: MC
authors.lastname: Torrente
authors.forename: Carolina
authors.initials: C
authors.lastname: Ríos
authors.forename: Carlos
authors.initials: C
authors.lastname: Misad
authors.forename: Roxana
authors.initials: R
authors.lastname: Ramírez
authors.forename: Monica
authors.initials: M
authors.lastname: Acuña
authors.forename: Lucia
authors.initials: L
authors.lastname: Cifuentes
mesh_terms: D001706:Biopsy; D004273:DNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification*; D005557:Formaldehyde / Q000737:chemistry; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D021141:Nucleic Acid Amplification Techniques; D016612:Paraffin Embedding / Q000379:methods*; D016707:Tissue Fixation / Q000379:methods*
chemical_list: D004273:DNA, Neoplasm; D005557:Formaldehyde