BUFFALO, NY – There is growing evidence for a link between the immune system and the control of cancer. Support for this link comes from observations that the immune system can protect against the development of spontaneous and chemically-induced tumors in laboratory systems. Further, a large number of targets for immune recognition of human cancer have been identified and characterized.

Results of a large study published in Proceedings of the National Academy of Sciences, Early Edition (www.pnas.org/cgi/doi/10.1073/pnas.0509182102) provide further evidence for the role of the immune system in controlling cancer.

The international research team, led by investigators from Roswell Park Cancer Institute (RPCI) and the global Cancer Vaccine Collaborative, examined the precise location of subpopulations of immune cells [tumor infiltrating lymphocytes (TILs)] in 117 Roswell Park patients with epithelial ovarian cancer (EOC) to determine the interrelationship between subpopulations of TILs and overall survival.

Results of the detailed immunohistochemical analysis of TILs in EOC indicated that although most subtypes correlated with each other, intraepithelial CD8⁺ was the only subtype associated with a favorable prognosis. Further, high CD8⁺/CD4⁺ and CD8⁺/regulatory T cell (Tregs) ratios were associated with a favorable prognosis in EOC; the latter corresponding to an almost 70 percent reduction in the risk of death.

“This work represents a major step forward in documenting evidence for immune responses to cancer,” according to Kunle Odunsi, MD, PhD, departments of Gynecologic Oncology and Immunology at RPCI and corresponding author of this study. “Further, it implies that a critical balance must be achieved in the ratio of CD8⁺ to Tregs in immune therapies, and that manipulation of Tregs could be a powerful method to enhance the efficacy of such therapies.”

This work was supported by a Cancer Vaccine Collaborative Grant from the Cancer Research Institute (CRI) and the Ludwig Institute for Cancer Research, and an Anna-Marie Kellen Clinical Investigator Award from the CRI to Dr. Odunsi.

Roswell Park Cancer Institute, founded in 1898, is the nation’s first cancer research, treatment and education center and is the only National Cancer Institute-designated comprehensive cancer center in Upstate New York. RPCI is a member of the prestigious National Comprehensive Cancer Network, an alliance of the nation’s leading cancer centers. For more information, visit RPCI’s website at www.roswellpark.org, call 1-877-ASK-RPCI or e-mail askrpci@roswellpark.org.

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