We first screened ten different colorectal cancer cell lines for expression patterns of CEACAM5 and HLA-I by flow cytometry analysis (Table S3), and chose four cell lines with different expression patterns for further studies, SW480 (CC4-, HLA-Ihigh), LS174T (CC4+, HLA-Ihigh), HCT-15 (CC4-, HLA-Ilow) and Lovo (CC4+, HLA-Ilow). This evidence concerns the gene CEACAM5 and colorectal cancer.