To further determine whether other molecular pathways are involved in T cell dysfunction in CRC patients, we studied Tim-3 and PD-1 expression on CD8+ T cells of circulating, tumor-infiltrating lymphocytes (TILs) and paraneoplastic tissues from patients with CRC and investigated clinical relevance of co-inhibitory molecules in circulating and TILs in CRC. Here, PDCD1 is linked to colorectal carcinoma.