RT-PCR screening of gastrointestinal (pancreatic, gastric, and colorectal) cancer cell lines was conducted using newly designed RT-PCR primers for several exons on the target gene and a primer pair spanning the region from exon 2 to exon 9 on the full-length CEACAM5 registered in GenBank (NM_004363; Figure 1). The gene discussed is CEACAM5; the disease is cancer.