Specific gene silencing using small hairpin RNA (shRNA) constructs offer researchers the possibility to study the influence of a single protein in the metastatic process. The role of the cellular adhesion molecule CEACAM1 on tumour formation and metastasis is of some interest. The human melanoma cell line FemX-1 was transfected with an shRNA construct directed against the CEACAM family. Stable clones were obtained and characterized via puromycin selection, single-cell dilution, and subsequent FACS analysis. The cell line showed a knock-down of CEACAM1 of more than 85%. This knock-down remained stable when examined in an SCID mouse xenograft experiment over 40 days.