Genomic DNA from primary EAC samples and a control samples was amplified by PCR, digested by SCRF1, and analyzed by gel electrophoresis. G/G homozygotes are represented by a single band at 146 bp, A/A homozygotes by a single band at 167 bp, and G/A heterozygotes by the presence of both bands. The 21 bp fragment can not be seen on this gel. Control samples were included in triplicate, along with the negative controls: control sample without enzyme and a no-template control. Genotypes were verified by TaqMan PCR.