Cellular crosstalk of regulatory T cells in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid tumors and is characterized by dense desmoplasia and immune desert. Regulatory T cells (Tregs) are critical components of the immune tumor microenvironment (TIME) of PDAC. Treg-induced immune evasion presents a significant hurdle in enhancing the efficacy of conventional and emerging therapeutic strategies. Nonetheless, Treg deficiency alone led to inconsistent outcomes. To unveil the underlying potential reasons for these results and to determine the role of Tregs in other therapeutic strategies, in-depth insights into the crosstalk between Tregs and other cells in PDAC are indispensable and currently lacking. Therefore, in this review, we comprehensively delineate the direct and indirect interplay between Tregs and various cellular constituents ranging from cancer cells and immune cells to stromal cells in PDAC in an attempt to uncover potential leads for the development of Treg-associated therapies.