Abstract LB-310: FISH-based determination of HER2 status in circulating tumor cells isolated with the microfluidic CEE™ platform

Abstract

Abstract Purpose: Determination of HER2 status by immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH) in patients with breast cancer is considered standard practice for selection of treatment options. Though patients presenting with recurrent and/or metastatic disease are often re-evaluated for HER2, biopsy is not often feasible. Thus, circulating tumor cells (CTCs) are an attractive alternative source of tumor tissue for determining HER2 status to enable a more effective course of treatment. Experimental Design: Twenty to thirty ml of peripheral blood was collected prospectively from 54 patients diagnosed with late stage metastatic/recurrent breast cancer. CTCs were isolated using the microfluidic CEE™ platform. CTC capture was achieved using a cocktail of capture antibodies, followed by detection with an expanded anti-cytokeratin (CK) cocktail mixture and anti-CD45. HER2 amplification was subsequently assessed by FISH on captured CK+/CD45− and CK−/CD45− cells. Results: CK+/CD45− cells were detected in 43 of 54 cases (80%). Among the 43 cases in which CK+ cells were detected, high concordance (93%) in HER2 status between primary tumor (by IHC and FISH) and CTCs (by FISH) was observed. An overall sensitivity of 95% and a specificity of 92% were obtained using the OncoCEE-BR™ assay. Conclusions: Recovery of CTCs from peripheral blood using the CEE™ platform is shown to be efficient and suitable for FISH-based testing. In addition, HER2 FISH on recovered CTCs is proven to be sensitive and accurate. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-310. doi:10.1158/1538-7445.AM2011-LB-310