Prognostic Role of HER-2 according to Lymph Node Involvement in Invasive Ductal Carcinoma of Breast

ABSTRACT

PURPOSE: This study was conducted to investigate the prognostic value of HER2 in breast cancer patients. METHODS: A total of 100 consecutive formalin-fixed, paraffin- embedded sections of invasive ductal carcinomas were evaluated by immunohistochemical staining (IHC) and a fluorescence in situ hybridization (FISH) assay for HER2. The cases of 0/1+ IHC were regarded as negative and 3+ as positive. Among the 100 cases tested by IHC, the 2+ cases were confirmed by FISH. RESULTS: Twenty-seven of 100 cases (27%) were confirmed positive for HER-2, which was significantly correlated with the nuclear grade (NG), ER and PR (P=0.014, P=0.004, and P=0.023, respectively). The mean disease-free survival periods (DFS) and overall survival periods (OS) of the HER-2-positive and -negative patients were 64.6+/-6 months and 82+/-3 months (P=0.0031), and 70+/-6 months and 85+/-2 months, respectively (P=0.0096). Of the 48 axillary lymph node (LN) positive patients, the mean DFS and OS of the HER-2-positive and -negative patients were 46+/-9 months and 80+/-4 months (P=0.0007) and 54+/-9 months and 83+/-4 months, respectively (P= 0.001). In the LN negative patients; however, HER-2 overexpression showed no significant correlation with the prognosis. In a multivariate analysis, DFS was significantly correlated with LN involvement and HER-2 overexpression (P=0.015, and P=0.0396, respectively). However, with regard to the OS. LN involvement and NG were statistically significant (P=0.041, and P=0.0125, respectively). CONCLUSION: This study indicates that HER-2 overexpression may play a useful role as an indicator of poor prognosis in invasive ductal carcinoma of breast, especially in LN positive patients.