CEACAM1 is differentially expressed in normal human tissues. (A) Schematic diagram of RT-PCR strategy for the identification of CEACAM1 long and short cytoplasmic domain splice variants. Binding sites for the forward and reverse primers and the expected size of amplified fragments are shown. The PCR amplified products were separated by electrophoresis on a 2.5% agarose gel. M, refers to 100 bp DNA ladder (NEB). (B) Histogram shows CEACAM1-S/CEACAM1-L (S:L) ratio quantified with NIH ImageJ program.