Tissue microarray-based study of patients with lymph node-negative breast cancer shows that HER2eu overexpression is an important predictive marker of poor prognosis.

摘要

BACKGROUND: Despite good prognosis in most cases of lymph node (LN)-negative breast cancer, individual patients may have markedly different clinical outcomes. Here, we investigated the prognostic significance of HER2eu overexpression in these tumors. MATERIALS AND METHODS: We employed a tissue microarray to examine HER2eu overexpression by immunohistochemical staining in 359 consecutive patients diagnosed with LN-negative breast cancer, who underwent surgery from January 1993 to December 1998. RESULTS: HER2eu overexpression was detected in 81 of 359 (23.1%) patients. The 10-year disease-free survival (DFS) values (81.2% versus 61.8%, P value 0.000) and overall survival (OS) rates (85.7% versus 63.9%, P value 0.000) were significantly different between cases with HER2eu-negative or HER2eu-positive tumors. After multivariate analysis, HER2eu status and tumor size were identified as independent prognostic factors for 10-year OS. Moreover, HER2eu overexpression was significantly associated with poorer clinical outcomes in an intermediate-risk group identified by the St Gallen classification (10-year DFS, 79.6% versus 61.8%, P value 0.000; 10-year OS, 84.7% versus 63.9%, P value 0.000). CONCLUSIONS: Our results show that HER2eu overexpression is an important independent prognostic factor for LN-negative breast cancer cases and support the theory that more intensive adjuvant chemotherapy is required in the population with HER2eu overexpression.