Sporadic colorectal cancer (CRC) is one of the most common and lethal cancers worldwide. The locations and functions of immune cells in the colorectal tumor microenvironment are complex and heterogeneous. T-helper (Th)1 cell-mediated responses against established colorectal tumors are associated with better outcomes of patients (time of relapse-free or overall survival), whereas Th17-cell mediated responses and production of interleukin 17A (IL17A) have been associated with worse outcomes of patients.