biostudies-literatureUnknown6(5)Xu L<h4>Background</h4>CD4(+)CD25(+) regulatory T cells (Tregs), a heterogeneous population, were enrichment in tumor mass and played an important role in modulating anti-tumor immunity. Recently, we reported a Treg subset, CCR6(+) Tregs but not CCR6(-)Tregs, were enriched in tumor mass and closely related to poor prognosis of breast cancer patients. However, the underlying mechanism remains elusive. Here, we carefully evaluate the enrichment of CCR6(+)Tregs in tumor mass during progression of breast cancer and explore its possible mechanism.<h4>Methodology/principal findings</h4>The frequency of CCR6(+)Tregs in tumor infiltrating lymphocytes (TILs ) was analyzed at early stage and at late stage of tumor in a murine breast cancer model by FACS respectively. The expansion of CCR6(+)Tregs and thPloS onee20282https://www.ebi.ac.uk/biostudies/studies/S-EPMC3105045biostudies-literatureIn situ prior proliferation of CD4+ CCR6+ regulatory T cells facilitated by TGF-β secreting DCs is crucial for their enrichment and suppression in tumor immunity.PMC3105045Xu LWen ZXiong SXu WfalseIn situ prior proliferation of CD4+ CCR6+ regulatory T cells facilitated by TGF-β secreting DCs is crucial for their enrichment and suppression in tumor immunity.<h4>Background</h4>CD4(+)CD25(+) regulatory T cells (Tregs), a heterogeneous population, were enrichment in tumor mass and played an important role in modulating anti-tumor immunity. Recently, we reported a Treg subset, CCR6(+) Tregs but not CCR6(-)Tregs, were enriched in tumor mass and closely related to poor prognosis of breast cancer patients. However, the underlying mechanism remains elusive. Here, we carefully evaluate the enrichment of CCR6(+)Tregs in tumor mass during progression of breast cancer and explore its possible mechanism.<h4>Methodology/principal findings</h4>The frequency of CCR6(+)Tregs in tumor infiltrating lymphocytes (TILs ) was analyzed at early stage and at late stage of tumor in a murine breast cancer model by FACS respectively. The expansion of CCR6(+)Tregs and th2011-01-01T00:00:00Z20112025-07-08T03:12:45.243Z2025-07-08T03:12:45.243ZS-EPMC31050452165525010.1371/journal.pone.0020282