Abstract 3071: Accurate and sensitive detection of KRAS mutations in heterogeneous cancer specimens

Abstract

Abstract The discovery of pivotal genetic alterations and the understanding of their role in cancer is leading to remarkable successes in therapeutics and patient care. Molecular diagnosis methods such as DNA sequencing and conventional genotyping of tumor biopsies have advanced research in this field, but are limited in sensitivity due to stromal contamination and by genetic heterogeneity in cancer. We have recently developed competitive allele specific TaqMan® PCR (castPCR) assays assays for detecting cancer-associated sequence variations. CastPCR not only maintains the wide dynamic range, high sensitivity and reproducibility of TaqMan® assays but also greatly improves the specificity. The technology enables detection, of as little as 1 mutant allele molecule in 10,000,000 wild type molecules. We report here sensitive and accurate detection of cancer-associated KRAS mutations within formalin-fixed paraffin-embedded (FFPE) heterogeneous cancer specimens. Eight FFPE model cell lines were initially used to validate the assays (NCI-H2009:p.G12A; SW1463:p.G12C; PANC-1:p.G12D; PSN-1: p.G12R; A549:p.G12S; SW480:p.G12V; DLD-1:p.G13D; Jurkat:Wild Type). Mutant FFPE cell line DNAs were titrated in the FFPE wild type cell line DNAs from 100% to 0.1%. Mutations were easily identified at the level of 0.1% with high reproducibility. 24 anonymous tumor tissues and 12 non-tumor tissues from FFPE specimens were also examined. No positive samples were found in non-tumor tissues. The results obtained by castPCR for the 24 tumor tissues were concordant to those previously reported by three different methods (Taqman® PCR, Taqman® PCR + PNA and Sequencing). Our results demonstrate that castPCR, as a new rare mutation detection technology, has greater sensitivity, specificity and can thereby facilitate accurate molecular diagnosis of heterogeneous cancer specimens and enable patient selection for targeted cancer therapies. 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 3071. doi:10.1158/1538-7445.AM2011-3071