RESUMEN
ObjectiveTo rapidly detect the mutation frequency of DBC2 gene 7776C ＞ T in breast cancer and breast fibroadenoma by applying the mutation-sensitive molecular switch ( comprised of high-fidelity DNA polymerase and phosphorothioate-modified allele-specific primers) and agarose gel electrophoresis.Methods Allelic specific primers targeting mutation type and wild type were designed with the primers'3'terminal phosphorothioate modification.When the primers matched with the tissue DNA,the primers could be extended with highfidelity polymerase; when they mismatched with the tissue DNA,the primers could not be extended.DNA samples from 85 cases of breast cancer and 10 cases of breast fibroadenoma tissues were chosen and analyzed by PCR amplifications mediated by high-fidelity DNA polymerase.Gel imaging system was employed to make analysis of PCT products.ResultsThe mutation-sensitive molecular switch system showed that the mutation rate of 7776C ＞ T was 2.4％ ( 2/85 ) in the 85 cases of breast cancer,and no mutation was found in the 10 cases of breast fibroadenoma.ConclusionsThe mutation-sensitive molecular switch combined with agarose gel electrophoresis can rapidly detect the mutation of breast cancer DBC2 gene 7776C ＞ T.It is applicable in single nucleotide polymorphisms assay and has enormous application value in detecting gene mutation.