Figure 4: Comparison of the efficiency of DNA extraction by examining the EGFR mutation in different amounts of FFPE tissue. (a) Ammonium sulfate DNA extraction method; (b) Pinpoint Slide DNA Isolation System; (c) TaKaRa DEXPAT; PTC: papillary thyroid carcinoma. 1: whole tissue; 2: 1/2 of one section; 3: 1/4 of one section (2 mm circle with a 4 µm thickness).