CEACAM5 and breast cancer: Lastly, through exome sequencing, Li et al. observed loss of heterozygosity of CEACAM1, CEACAM3, CEACAM5, CEACAM6, CEACAM7, and CEACAM8 in breast cancer tumors that were associated with metastasis, suggesting that this closely-linked gene family regulates tumorigenesis and metastasis synergistically (Li et al., 2014).