Table 3: Successful β-globin gene amplification frequency using DNA extracted from various numbers of PTC cells on archival smear slides using the three different methods.

No. of cellsABC
No. of β-globin amplificationP value*No. of β-globin amplificationP value*No. of β-globin amplificationP value*

25
( )
90.01100.00230.206
50
( )
90.01130.20640.527
100
( )
100.00280.05880.058
200
( )
100.00280.05880.058
500
( )
100.002100.00290.011
1000 ( )100.002100.002100.002

A: ammonium sulfate DNA extraction method; B: Pinpoint Slide DNA Isolation System; C: TaKaRa DEXPAT; PTC: papillary thyroid carcinoma. *Two-tailed Fisher's exact test.