Hereditary breast cancer BRCA1/2 methylation and survival analysis

OBJECTIVE To investigate the effect of BRCA1/2promoter methylation status,clinical and pathological features on survival in patients with hereditary breast cancer.METHODS Seventy-four patients with breast cancer were diagnosed by pathology from January 1st,2005 to January 1st,2011 of breast surgery,Tumor Hospital Affiliated to Xinjiang Medical University.The methylation status of BRCA1/2gene promoter were detected in all the 74 patients.The related clinicopathological characteristics were collected(age,genetic background,tumor size,lymph node metastasis,molecular subtypes,tumor grade,clinical stage).Cox regression model was used to analyze the influencing factors of survival time.RESULTS The rate of BRCA1/2promoter methylation was 32.43%(24/74).BRCA1 gene promoter methylation rate was 25.68%(19/74),BRCA2 gene promoter methylation rate was 6.76%(5/74),the difference was statistically significant(χ2=9.747,P=0.002).Univariate analysis showed that tumor size(χ2=15.927,P<0.001),lymph node metastasis(χ2=20.490,P<0.001),clinical stage(χ2=39.589,P<0.001)and molecular subtypes(χ2=15.093,P=0.001)were the key factors influencing the survival time,the difference was statistically significant.Multivariate analysis showed that clinical stage and molecular subtypes were the major risk factors for survival time(The OR values were 1.436and2.181).CONCLUSIONS BRCA1/2promoter methylation status of hereditary breast cancer is not a major factor impacting survival time.HER-2over expression and late clinical stage suggests the poor prognosis in hereditary breast cancer.