Tumor-infiltrating Immune Cells in H&E-stained Sections of Colorectal Cancer Tissue as a Reasonable Immunological Biomarker

Background: The density of tumor-infiltrating lymphocytes has been reported to reflect the antitumor immune status, and many reports have shown that tumor-infiltrating CD8+ and total T-lymphocytes may be strong prognostic biomarkers in colorectal cancer. We previously reported that the density of tumor-infiltrating immune cells in hematoxylin and eosin (H&E)-stained sections may be an easily available prognostic biomarker. However, it remains unclear whether the density of tumor-infiltrating immune cells in H&E-stained sections accurately reflects the antitumor immune status. Patients and Methods: A total of 308 patients who underwent curative resection for stage 111111 colorectal cancer were enrolled. The density of both tumor-infiltrating immune cells in H&E-stained sections and tumor-infiltrating lymphocyte subsets was assessed by immunohistochemistry. Results: The density of tumor-infiltrating immune cells in H&E-stained sections was significantly and positively correlated with that of tumor infiltrating CD4+ 1CD8+ ltotal T-lymphocytes. Conclusion: The density of tumor-infiltrating immune cells in H&E-stained sections may be a reasonable immunological biomarker.