Kong JC, et al. - Researchers investigated the prognostic and predictive value of tumor-infiltrating lymphocytes (in neoadjuvant setting) for metastatic colorectal cancer by analyzing a total of 25 studies, including 15 for primary colorectal cancer (4,719 patients), 7 for locally advanced rectal cancer (727 patients), and 3 for metastatic colorectal cancer (418 patients). They observed improved overall survival for primary colorectal cancer in correlation with high CD3⁺, CD8⁺, FoxP3⁺, and CD45RO⁺ densities, with pooled estimated HRs of 0.88, 0.81, 0.70, and 0.63, respectively. Furthermore, they identified significant predictive value of CD8⁺ cell levels for good tumor regression grade after chemoradiotherapy in locally advanced rectal cancer.