Caveolin-1 is responsible for the development of caveolae, which are vesicular invaginations of the plasma membrane, and plays a key role in membrane traffic and signal transduction. The role of caveolin-1 in carcinogenesis has been a subject to numerous investigations, however, the expression pattern and the function of caveolin-1 are rather controversial both in gastrointestinal and extraintestinal cancers. The vast majority of results based on cancer cell line experiments indicate that caveolin-1 might act as a tumor suppressor gene. In tumor tissues, however, caveolin-1 seem to fulfill a tumor promoting role, since the expression of caveolin-1 is increased when compared to normal tissue counterparts. In this review, the authors summarize the results of caveolin-1 expression in gastrointestinal and extraintestinal cancer emphasizing possible future therapeutic implications.