Association of HER-2/neu overexpression with the number of involved axillary lymph nodes in hormone receptor positive breast cancer patients.

Aim: To evaluate the prognostic significance of HER-2/neu overexpression in hormone receptor and axillary lymph node positive breast cancer patients treated in a single institution.

Methods: Paraffin-embedded primary breast cancers from 40 patients with invasive ductal carcinoma were studied immunohistochemically. HER-2/neu staining was classified as negative (0, 1+), weak/moderate positive (2+), or moderate/strong positive (3+) and was assessed for effectiveness as a predictor of outcome in univariate and Cox model multivariate analyses.

Results: 20% of patients were positive for HER-2/neu. Significant associations were observed between HER-2/neu and increasing number of involved nodes (p = 0.014), p53 positivity (p = 0.039), the presence of vascular invasion (p = 0.029) and metastases (p = 0.01). Multivariate analysis demonstrated that HER-2/neu overexpression (p = 0.016) and age (p = 0.005) were independent predictors for disease-free survival (DFS) where the number of involved nodes (p = 0.032) was shown to be independent predictor for overall survival. In the HER-2/neu positively stained tumors, significant number of patients developed distant metastases than the patients with HER-2/neu negatively stained tumors (87.5% vs 34.4%, p = 0.01).

Conclusion: For node positive patients, HER-2/neu overexpression was a significant predictor of DFS.