RFLP analysis of genetic polymorphism of the 160 site of the E-cad promoter. The C/A polymorphism was differentiated by BstEII digestion of PCR products homozygous for the wild-type (high-activity) allele (wt/wt, CC genotype), heterozygous for the variant (low-activity) allele (wt/vt, CA genotype), and homozygous for the low-activity allele (vt/vt, AA genotype).