Wg. Wang et al., PCR AMPLIFICATION OF 40-YEAR-OLD PARAFFIN-EMBEDDED TUMOR-TISSUES - COMPARISON OF 4 DIFFERENT DNA EXTRACTION AND PURIFICATION METHODS, International journal of oncology, 5(3), 1994, pp. 453-457
Four different methods of DNA extraction from formalin-fixed, paraffin
-embedded tissues were compared for their ability to produce DNA suita
ble as a template for polymerase chain reaction (PCR). Seven paraffin-
embedded rhabdomyosarcoma tissue blocks from the 1950s and one from 19
60 were treated with the following extraction methods: 1. Proteinase K
digestion and phenol/chloroform extraction; 2. Proteinase K digestion
followed by boiling to inactivate the enzyme; 3. Proteinase K digesti
on, addition of Chelex-100, followed by boiling; and 4. Proteinase K d
igestion and Prep-A-Gene purification. DNA extracted by methods 1 and
2 was degraded, but DNA of high molecular weight was recovered in ever
y sample extracted by methods 3 and 4 - even though some degradation w
as observed. Extracted DNA was used as a template for PCR amplificatio
n of exon 4 of the PAX-3 gene. PCR was successful in 7 out of 8 sample
s prepared using methods 3 and 4, producing levels of amplified produc
t equivalent to those obtained with control DNA obtained from fresh ly
mphocytes. Only very weak products were found in samples prepared by m
ethods 1 (2 out of 8) and 2 (4 out of 8). These results indicate that
chelation of polyvalent ions (Chelex-100 method) or obviating the need
for boiling (Prep-A-Gene) may protect DNA during extraction.