Remarkably, the in vitro results from cell culture (increased in vitro proliferation and migration in the CEACAM1 kd) could not predict the melanoma cells’ in vivo behavior (decreased tumor growth and metastasis in the CEACAM1 kd) whereas the xenograft model reflected the clinical situation quite well (high CEACAM1 expression is associated with high metastatic potential in xenograft models and with poor survival of patients, see also analyses discussed below). Here, CEACAM1 is linked to melanoma.