To the best of our knowledge, here we report the first study using mucin 1- and EpCAM-based immunomagnetic enrichment, followed by real-time RT-PCR analysis of KRT19, MUC1, EPCAM, CEACAM5 and BIRC5, as a way to detect and evaluate the prognostic and predictive effect of CTCs in PB of colorectal cancer patients. The gene discussed is KRT19; the disease is colorectal cancer.