Prognosis in hormon receptor negative breast cancer patients according to ERBB2 status

Breast carcinomas represent a heterogenous group of tumors and recent studies have demonstrated several subtypes of breast cancer by gene expression profiles. This study aimed to compare hormon receptor negative (ER-/PR-/ERBB2+) and triple negative (ER-/PR-/ERBB2-) patients in terms of prognosis and to show that molecularly defined subtypes can be distinguished by conventional laboratory methods. Patients treated between 2001-2007 for hormon receptor negative breast cancer were retrospectively studied. In addition to the conventional prognostic factors, effect of ERBB2 status of the patients on disease-free and overall survival was evaluated. Hormon receptor and ERBB2 status were determined by immunuhistochemistry and fluorescence in-situ hybridization. 141 patients were eligible for the study. Number of patients with ERBB2 positive and triple negative tumors was 70 and 71, respectively, and two groups were comparable in terms of study parameters. Tumor size, grade, axillary status, patient groups, and adjuvant chemotherapy and radiotherapy showed significant impact on disease-free survival and overall survival was significantly dependent on axillary status, type of surgery, and patient groups in univariate analysis. In multivariate analysis, patient groups, tumor grade, and axillary status were independent prognostic factors for disease-free survival whereas patient groups, extent of surgery, and axillary status were independent prognostic factors for overall survival. This study has indicated that ERBB2 negative patients had worse survival among hormon receptor negative breast cancer patients and showed that molecularly defined subtypes of breast cancer can be differentiated by immunuhistochemistry in terms of prognosis.