Prognostic value of natural killer cells in colorectal carcinomas

Abstract

Backgrounds: Although natural killer cells are considered valuable prognostic factors in several solid tumors, their role in colorectal carcinomas remains obscure. Thus, we aimed to determine the prognostic value of NK cells in colorectal carcinomas. Methods: We reviewed patients who were diagnosed with stage I to IV colorectal carcinomas and who underwent curative resection of the tumor. We first determined and marked the areas with the most important lymphocyte infiltration in the center and the invasive margin of the tumor. Subsequently, we identified natural killer cells by performing an immune histochemical study with a anti-CD56 antibody via the tissue microarray technique. Afterwards, we manually counted the marked cells. Multivariate analysis was performed to determine the independent prognostic factors for death. Results: Our study included 104 patients. The mean age was 61.6 ± 1.4 years. The median numbers of natural killer cells in the tumor center and in the invasive margin were 1/punch and 0/punch respectively. The median total number of natural killer cells/tumor was 2. The total number of natural killer cells was ≥ 2 in 49 (47.1%) tumors. No significant difference was found in the survival curves between the group of tumors with Natural Killer cells ≥ 2 and that with Natural Killer cells < 2 (p = 0.117). According to multivariate analysis, a low immunoscore and the histological subtype of mucinous adenocarcinomas were found to be independent prognostic factors associated with poor overall survival. Conclusion: There are few natural killer cells in tumor tissue. They have no prognostic impact on the overall survival of patients with colorectal carcinomas. Trial registration: The Habib Thameur Hospital Ethics Committee HTHEC-2023-23 (retrospectively registered)