CEACAM1 and colon adenocarcinoma: The role of CEACAM proteins in SCLC is unknown, but high surface expression of CEACAM1 is associated with microvessel density, distant metastases, and shorter median overall survival in non-small cell lung cancer, whereas high surface expression of CEACAM6 is associated with poor tumor differentiation in colon adenocarcinoma [38,39].