GLUTAMINE AND CANCER

Objective: This overview on glutamine and cancer discusses the importa nce of glutamine for tumor growth, summarizes the alterations in inter organ glutamine metabolism that develop in the tumor-bearing host, and reviews the potential benefits of glutamine nutrition in the patient with cancer. Summary Background Data: Glutamine is the most abundant a mino acid in the blood and tissues. It is essential for tumor growth a nd marked changes in organ glutamine metabolism are characteristic of the host with cancer. Because host glutamine depletion has adverse eff ects, it is important to study the regulation of glutamine metabolism in cancer and to evaluate the impact of glutamine nutrition in the tum or-bearing state. Methods: Data from a variety of investigations on gl utamine metabolism and nutrition related to the host with cancer were compiled and summarized. Results: Numerous studies on glutamine metabo lism in cancer indicate that many tumors are avid glutamine consumers in vivo and in vitro. As a consequence of progressive tumor growth, ho st glutamine depletion develops and becomes a hallmark. This glutamine depletion occurs in part because the tumor behaves as a ''glutamine t rap'' but also because of cytokine-mediated alterations in glutamine m etabolism in host tissues. Animal and human studies that have investig ated the use of glutamine-supplemented nutrition in the host with canc er suggest that pharmacologic doses of dietary glutamine may be benefi cial. Conclusions: Understanding the control of glutamine metabolism i n the tumor-bearing host not only improves the knowledge of metabolic regulation in the patient with cancer but also will lead to improved n utritional support regimens targeted to benefit the host.