CEACAM1 and neoplasm: Dichotomous roles have been assigned to CEACAM1 in tumor development and progression: on the one hand, its expression has been correlated to increased tumor invasion in melanoma, lung carcinoma, in carcinomas of the thyroid, liver and colon; in these specimens, CEACAM1 is up- regulated during progression of the disease and has been established as an independent prognostic marker [57, 58].