Abstract
RP-34
Circulating tumor cells in blood from metastatic breast and lung cancer patients have been reported as a surrogate marker for tumor response and shorter survival.Detection of these rare tumor cells in blood is important for early cancer diagnosis. Here we report a new competitive allele-specific TaqMan-based PCR (castPCR) method for rare mutation detection.castPCR combines allele-specific TaqMan qPCR with allele-specific MGB blockers to suppress amplification of the wild type allele, resulting in better specificity. We have successfully designed and validated castPCR assays for 48 cancer-related SNPs of Ras, EGFR, Kit, pTEN, and p53. Results demonstrate that castPCR not only maintains the wide dynamic range, high sensitivity, and reproducibility of conventional TaqMan assays but also improve assay specificity of detecting rare mutant alleles for up to 1 in 10,000,000. Results of detecting circulating tumor cells in cancer patient samples will be presented.