Samples from patients with CRC or IBD, and healthy controls were examined to address three questions: is the frequency of Treg (CD25hiCD4+FOXP3+ T cells) increased in blood or lymph nodes from patients with CRC; can anti-tumor T cell responses to 5T4 be identified in CRC patients; and do Treg impinge on these anti-tumor immune responses? Here, FOXP3 is linked to inflammatory bowel disease.