Primary tumor immune score fails to predict the prognosis of colorectal cancer liver metastases after hepatectomy in Chinese populations

BACKGROUND: Increasing evidence suggests that the immune score is significantly associated with cancer prognosis. However, the prognostic role of primary tumor immune score in colorectal cancer liver metastases (CRLM) after hepatectomy in Chinese patients has not been reported. The present study is designed to investigate whether the immune score of primary tumor can predict the postoperative survival of liver metastases in Chinese patients. METHODS: A total of 131 patients diagnosed with CRLM were included, and the corresponding primary tumor and liver metastasis specimens were acquired. An immune score ranging from 0 to 4 was established based on the counts and densities of CD3(+) and CD8(+) T cells in the core tumor (CT) and the invasive margin (IM). Relapse-free survival (RFS) and overall survival (OS) were analyzed by Kaplan-Meier curves to assess the prognostic role of primary tumor immune score. Furthermore, we conducted a comprehensive search of the Gene Expression Omnibus (GEO) and selected stage IV colorectal cancer (CRC) patients with liver metastasis to compare the tumor-infiltrating T cell profiles of the primary tumor and liver metastases by CIBERSORT. RESULTS: Patients with high immune scores in the primary tumor has no significantly better RFS and OS after hepatectomy than those with low immune scores [median RFS (95% CI): 19.13 (10.07–28.20) vs. 27.13 (15.97–38.29) months, P=0.604; median OS (95% CI): 64.37 (35.96–92.78) vs. 40.07 (32.54–47.59) months, P=0.652]. Data collected from the GEO indicates that the proportion of CD8(+) T cells and total T cells in the primary tumor and liver metastatic lesion are also not significantly correlated (CD8(+) T cells: r(2) =0.030, P=0.468; total T cells: r(2) =0.165, P=0.076). CONCLUSIONS: The immune score of the primary tumor fails to predict the prognosis of CRLM after hepatectomy in Chinese patients.