Mast cells, disease and gastrointestinal cancer: A comprehensive review of recent findings.

Paul Ehrlich, a German scientist, discovered what is known as the mast cell in the late 1800's, which has proven to be an important player in the immune system of vertebrates. Mast cells are ubiquitous throughout the tissues of the human body and play numerous roles, both beneficial and destructive. We know they are important in our army of immunity warrior cells, which defend us against viruses, bacteria and parasitic invaders. They are also very well known for the havoc they wreak, causing uncomfortable symptoms due to their release of histamine and other mediators which cause the all too familiar itching, sneezing, urticaria and rhinorrhea of allergic responses. Mast cell activities are diverse and include painful inflammatory reactions in autoimmune conditions such as rheumatoid arthritis. In the gastrointestinal system, mast cells are implicated in diverse actions such as increased gastric acid secretion, polyp formation and uncomfortable conditions such as Irritable Bowel Syndrome. The role of immunology and mast cells in these areas is intriguing but less well understood than their role in allergic responses. Because mast cells have been implicated in both physiologic as well as pathogenic processes, they have been the subjects of avid study. Review of the current literature on mast cell biology reveals that there are many studies of their presence within the tumor microenvironment and evidence, which supports mast cell influence on tumor angiogenesis, tumor invasion, and immune suppression. The studies reviewed in this article concentrate largely on mast cells in human GI malignancies. This review also provides background information regarding mast cells, such as their origination, their location within the body, how they are activated and how they function as mediators.