Correlation of HER2/neu expression by real-time qRT-PCR in the peripheral blood of locoregional breast cancer patients with time to progression.

Abstract

e11059 Background: HER2/neu is a membrane receptor overexpressed in about 20% of Breast Cancer (BC) patients which can be targeted by several agents. As an epithelial marker it can also be detected by qRT-PCR in the peripheral blood (PB) of BC patients reflecting the presence of circulating tumor cells (CTCs). Objectives: Evaluate the prognostic impact of Her2/neu expression detection in the PB of BC patients. Methods: We performed qRT-PCR for HER2/neu serially at entry into the study and at every 3 months intervals for up to 2 years in every patient. Our qRT-PCR used primers described in Ferreira et al, 2010. In our hands this method could detect 1 MCF-7 cell diluted in 1x104 mononuclear cells and had a specificity of 83% (4/22 normal women controls had a positive test). Results: from 02/20/08 to 02/09/10 we included 41 patients with a histopathological diagnosis of BC with a mean age of 54 years (range 29 to 83 years); 55% post-menopausal; stages I:12%, II:41% and III:46%; 58% and 51% were ER+, 64% PR+, and 25% cerb2 positive (+++). The patients were treated with adjuvant and 41% with neoadjuvant chemotherapy with anthracycline regimens including anthracyclines in 88% and taxanes in 75%. With a mean follow up of 28 months, only HER2/neu expression at study entry as a continuous variable (HR = 1.125 95% CI: 1.021 – 1.238) and disease stage (HR = 6.34 95% CI 1.30 – 30.82) correlated significantly with time to progression by multivariate analysis. HER2/neu expression did not correlate with HER2/neu tissue expression. Conclusions: HER2/neu expression by Real Time RT-PCR in the PB of BC patients is a potential new prognostic factor for BC patients with locorregional disease.