DNA genotyping of unbuffered formalin fixed paraffin embedded tissues.
Formalin-induced DNA degradation was studied at different fixation times (3, 7, 16 and 32 days) each on 10 formalin fixed paraffin embedded tissues (FFPET) stored for 15 years at room temperature. The four different extraction protocols used in this study showed that Chelex100 extracts performed the best at 3 and 7 days of formalin fixation (DFF) (with regard to the quantity and the quality of the DNA). However, Qiamp extracts showed better results for long sized alleles, as well for single polymerase chain reaction (PCR) amplifications after 16 and 32 DFF, as for multiplex PCR at shorter fixation times. DNA degradation is expressed by the size of the amplified alleles, only 100 bp templates surviving after 32 DFF (AMG locus). Single locus amplifications (CD4 and FES/FPS alleles) performed better than multiplex PCR (ProfilerPlus), with nearly 100% positive results at 7 DFF. In both types of amplifications, the success rate decreased proportionally with the time of formalin fixation and, consequently, with the size of the required DNA template.
Legrand
Beatrice
B
Département universitaire de médecine légale et droit médical, Université René Descartes, 45, rue des Saint Pères, 75270 Paris Cedex 06, France.
Mazancourt
Philippe de
Pd
Durigon
Michel
M
Khalifat
Véronique
V
Crainic
Karine
K
D000483:Alleles; D016172:DNA Fingerprinting / Q000379:methods*; D005404:Fixatives; D005554:Forensic Medicine / Q000379:methods*; D005557:Formaldehyde; D006801:Humans; D009926:Organ Preservation / Q000379:methods*; D010232:Paraffin; D016133:Polymerase Chain Reaction / Q000379:methods*; D020080:Tandem Repeat Sequences / Q000235:genetics
D005404:Fixatives; D005557:Formaldehyde; D010232:Paraffin