Recently Ouhtit et al. [27] found that overexpression of METCAM inhibited the in vitro invasiveness of MDA-MB-231 cells, supporting the notion of Shih et al. On the contrary, Garcia et al. [28] and Zabouo et al. [29] supported the opposite role of METCAM in the progression of human breast cancer cells in that it plays a role of tumor promoter. The gene discussed is MCAM; the disease is breast cancer.