Nicholas D. Klemen, M.D.

Assistant Clinical Investigator

Surgery Branch


CRC Building 10, Room 3-5942
Bethesda, MD 20892


Research Topics

For some patients with advanced cancer, immunotherapy can mediate complete and durable regression of widely metastatic disease. However, most gastrointestinal cancers, including 95% of colon cancers and nearly all pancreatic cancers, do not respond to the FDA-approved immunotherapy regimens that have proven to be effective for patients with other types of cancers.

In the Surgery Branch, we are performing bench-to-beside research to enhance the function of the immune system by preserving and regenerating T cell function, and are engineering T cells to efficiently target unique cancer mutations. Finally, we are investigating fundamental aspects of cancer cell biology to make cancer cells more visible to the immune system.

We are translating this research through our adoptive cellular immunotherapy platform for patients with unresectable or metastatic gastrointestinal cancers. Also, for patients with surgically resectable but high risk tumors, we are developing novel combinatorial immunotherapy treatments that may help stimulate immune responses and prevent tumor recurrence.


Nicholas Klemen, M.D., is a surgical oncologist at the National Cancer Institute (NCI) in Bethesda, Maryland. He earned his B.S. and M.D. degrees from Indiana University. Dr. Klemen received surgical training at Yale University and spent three years at the NCI completing a clinical fellowship in cancer immunotherapy and a research fellowship in immunotherapy and cellular reprogramming. After completion of his residency training, Dr. Klemen completed a clinical fellowship in complex general surgical oncology at Memorial Sloan Kettering Cancer Center where he gained further expertise in the management of cancers of the gastrointestinal tract, especially those of the colon, pancreas, and liver.

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This page was last updated on Thursday, July 13, 2023