Figure 5.

Tumor-infiltrating lymphocytes and tertiary lymphoid organs in colorectal cancer. The location and phenotype of CD3+ lymphocytes infiltrating the tumor tissue has been correlated with patient outcome (A).⁷³ Lymphocytes are also found in tumor-induced tertiary lymphoid organs/lymphoid follicles in the peritumoral area (B). Tumor-infiltrating lymphocytes could be recruited directly from the bloodstream following their activation in draining LN or in peritumoral TLO and release into the circulation, as outlined in Figure. 1. Lymphocytes activated in peritumoural TLOs could bypass the bloodstream and migrate directly into the adjacent tumor tissue. Lymphocytes in cryostat sections of tumors were stained either for CD3 (A) or mismatch repair enzyme MLH1 (B).