To analyze the feasibility of characterizing CTCs by the combined detection of multiple epithelial (EpCAM and CK8/18/19) and mesenchymal (VIM, TWIST1, AKT2 and SNAI1) markers, DLD-1 colorectal adenocarcinoma cells were spiked into 5 ml of blood from healthy donors. The gene discussed is SNAI1; the disease is colorectal adenocarcinoma.