Figure 1: Comparison of β-globin gene amplification using DNA extracted from various numbers of SNU 790 cells and PTC cells on archival smear slides. We compared PCR products amplified from DNA extracted using three different methods to determine the efficacy of DNA extraction. This assay used β-globin primers that amplify a 110 bp fragment of genomic DNA. (a) Ammonium sulfate DNA extraction method; (b) Pinpoint Slide DNA Isolation System; (c) TaKaRa DEXPAT; PTC: papillary thyroid carcinoma.