HER-2/neu Amplification Determined by Real-Time Quantitative PCR and Its Association with Clinical Outcome of Breast Cancer in Thailand

HER-2/neu has been found to be amplified or overexpressed in about 20-30% of breast cancers, in associationwith negative prognosticators and shortened survival. Determination of HER-2/neu status in breast-cancerpatients, to select for adjuvant treatment with trastuzumab, is becoming standard breast-cancer clinical practice.This study aimed to investigate HER-2/neu status in breast-cancer by real-time quantitative polymerase chainreaction (PCR), allowing accurate and precise quantification of HER-2/neu amplification in tumor tissues. Weevaluated 112 breast-cancer samples, of which 42 (37.5%) had HER-2/neu amplification. After a mean follow-upperiod of 71 months, HER-2/neu amplification was found to be significantly associated with increased risk ofdeath (HR = 6.367, 95% CI = 1.787-22.684), even after adjusting for age, clinical stage, tumor size, lymph-nodestatus, and histologic grade. These findings support a negative prognostic role for HER-2/neu in breast-cancersurvival. We suggest that real-time quantitative PCR analysis of HER-2/neu amplification represents an alternativetechnique for establishing HER-2/neu status in routine clinical practice.