Comparison of methods for DNA extraction from paraffin-embedded tissues and buccal cells

Both paraffin-embedded tissue specimens and buccal cells are excellent resources for large-scale molecular epidemiological studies. In order to identify the optimal method for DNA extraction, we compared three methods: (1) modified phenol–chloroform protocol; (2) simple boiling method; and (3) DNA Extraction Mini Kit. For paraffin-embedded tissue specimens, amplification of the β-globin gene sequence was successful in 30 of 34 (88.2%) by the simple boiling method, 29 of 34 (85.3%) samples using DNA extracted by the phenol–chloroform method, and 18 of 34 (52.9%) by the DNA Mini Kit. For buccal cells, amplification of the β-globin gene sequence was successful in 16 of 17 (94.1%) DNA samples extracted by the phenol–chloroform method, 2 of 16 (12.5%) by the simple boiling method, and 12 of 16 (75%) by the DNA Mini Kit. Both the simple boiling method and the phenol–chloroform method are better methods for DNA isolation from paraffin-embedded tissue specimens, and the phenol–chloroform method is the best method for DNA extraction from buccal cells.