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In this Letter, we omitted the following accession information. The digital gene expression matrix and the Helicos single-molecule sequence data from which it was derived are available at the NCBI GEO database with accession number GSE40176. A total of 44 samples were uploaded including 12 mouse and 32 human samples. Paired RNA sequencing data for epithelial cell adhesion molecule (EPCAM) and control immunoglobulin circulating tumour cell (CTC)-Chips from two pancreatic cancer mice, four human healthy donors, and 12 human metastatic pancreatic cancer patients are included in this data set.