Study on The Concordance of BIM Deletion Polymorphism Tests by Sanger Sequencing and Snapshot Methods in Breast Cancer

Objective The role of this essay is to explore the cocordance of Sanger sequencing and Snapshot methods for detecting the deletion polymorphism of BIM gene in breast cancer. Methods Surgical cancer tissue samples of a total of 336 cases with breast cancer were collected and preserved as formalin fixed paraffin embedded wax blocks. Genomic DNA was extracted and BIM gene deletion polymorphic in these breast cancer patients were detected by Sanger sequencing and Snapshot methods. Chi-square test with cross-tabular data was used to analyze the proportion of BIM deletion polymorphisms in patients with different clinical characteristics. Chi square test and Kappa coefficient test were used to detect the concordance degree of the two methods. Results In these 336 cases of breast cancers, 11.61% （39/336） cases were tested as positive with BIM deletion by Sanger sequencing. 13.99% （47/336） patients were positive with BIM deletion porlymorphism by Snapshot method. The Sanger sequencing method detected statistically significant differences in the expression of BIM mutations in breast cancer at different ages （χ²=6.242,P=0.044）and progestrone receptor levels（χ²=4.070,P=0.044）. The McNemar test showed the two methods had no statistical difference in the positivity of BIM gene deletion polymorphism （P=0.152）. Kappa coefficient test also indicated concordance between the two methods （κ=0.695, P=0.000）. Conclusions In this Chinese cohort of breast cancers, the BIM gene deletion polymorphism is around 11.61%. Sanger sequencing and Snapshot methods had consistency and might be complementary in the detection of BIM deletion polymorphism in breast cancer.