Examining Regulatory T Cells in Pancreatic Cancer

Regulatory T cells (Tregs) represent a prominent subset of immunosuppressive cells within the pancreatic tumor microenvironment. They exert influence on tumor growth by directly affecting cancer cells or by inhibiting effector immune cells. The mechanisms of Tregs interact within a partially redundant network with other immunosuppressive cells, such as MyeloidDerived Suppressor Cells (MDSCs), contributing to the robustness of tumor immunosuppression and resistance to immunotherapy. The findings from preclinical studies, which indicate a simultaneous decrease in MDSCs when Tregs are depleted in early tumors, but an inverse relationship in advanced Pancreatic Cancer (PCa), underscore the importance of a comprehensive assessment of the immunosuppressive profile throughout the progression of PCa. An insightful context for the examination of these intricate compensatory mechanisms could be the tumors of patients who have undergone Neoadjuvant Therapy (neoTx). Our observations reveal a concurrent reduction in intratumoral Tregs and MDSCs following neoTx, even in cases of locally advanced PCa. NeoTx also results in diminished levels of αSMA+ myofibroblastic Cancer-Associated Fibroblasts (myCAFs) and an increased presence of CD8+ cytotoxic T lymphocytes within the tumor.