Polymorphisms of CEA were surveyed using the NCBI singlenucleotide polymorphism (SNP) database (http://www.ncbi.nlm. nih.gov/projects/SNP). Two non-synonymous coding SNPs of CEA (rs10407503, rs7249230) were identified in the binding epitope of MEDI-565 (shown in Figure 2 ). The single-nucleotide C to A change in the SNP rs10407503 resulted in the amino acid change of Ala to Asp at the aa position 340. The single-nucleotide A to G change in the SNP rs7249230 encoded an aa change of Glu to Lys at the aa position 398. According to the SNP database, the minor allele frequencies in the population for rs10407503 are 0.014,0.267 and minor allele frequencies for rs7249230 are 0.03,0.3 in the population, respectively. However, the minor allele homozygosity rate for rs10407503 is close to 0 in both European and Asian populations and is 0.083 in Sub-Saharan African populations. The minor allele homozygosity rate for rs7249230 was from 0 to 0.068 in different populations. Since the homozygosity rates of both SNPs are very low, we anticipated the identified CEA SNPs to have little or no impact on MEDI-565 binding to CEA for these populations.