151 - Colonic Bacteria and the Tumor Immune Microenvironment of Colorectal Cancer Patients

A drastic difference exists between the 5-year survival rates of colorectal cancer patients with localized cancer and distal organ metastasis. The liver is the most favorable organ for cancer metastases from the colorectum. Beyond the liver-colon anatomic relationship, emerging evidence highlights the impact of liver immune microenvironment on colorectal liver metastasis. Prior to cancer cell dissemination, hepatocytes secrete multiple factors to recruit or activate immune cells and stromal cells in the liver to form a favorable premetastatic niche. The liver-resident cells including Kupffer cells, hepatic stellate cells, and liver-sinusoidal endothelial cells are co-opted by the recruited cells, such as myeloid-derived suppressor cells and tumor-associated macrophages, to establish an immunosuppressive liver microenvironment suitable for tumor cell colonization and outgrowth. Current treatments including radical surgery, systemic therapy, and localized therapy have only achieved good clinical outcomes in a minority of colorectal cancer patients with liver metastasis, which is further hampered by high recurrence rate. Better understanding of the mechanisms governing the metastasis-prone liver immune microenvironment should open new immuno-oncology avenues for liver metastasis intervention.

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Comparing of pan-cancer tumor immune microenvironment.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.e15100 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. e15100-e15100

Author(s):

Jiaan Ye ◽

Longgang Cui ◽

Xiaochen Zhao ◽

Guanghui Lan

Keyword(s):

Colorectal Cancer ◽

T Cells ◽

Natural Killer Cell ◽

Natural Killer ◽

Cancer Patients ◽

Killer Cell ◽

Immune Microenvironment ◽

Hepatobiliary Cancer ◽

Tumor Immune Microenvironment ◽

Pan Cancer

e15100 Background: Cancer treatment has entered the era of immune checkpoint inhibitors (ICI), but different tumors have different responses to ICI drugs. For example, non-small cell lung cancer and melanoma have higher response rates to ICIs than colorectal cancer and liver cancer patients. Previous studies have shown that tumor immune microenvironment have a great impact on the efficacy of ICI. Methods: This study retrospectively included pan-cancer patient specimens, using multiple fluorescent labeling immunohistochemistry to explore the differences in the immune microenvironment of different tumors. Shapiro-Wilk was used for normality test, and ANOVA or Kruskal Wallis test was used according to the results. Two-sided P < 0.05 was considered a significant difference. Results: The study included 308 patients, including 119 (38.6%) NSCLC patients, 72 (23.4%) Colorectal cancer patients, 51 (16.6%) Hepatobiliary cancer patients and 66 (21.4%) Others types of cancer patients. Among them, there was 192 (62.3%) Male, and 116 (37.7%) Female, and the median age was 57 (50-66). The proportion of CD8+ T cells and natural killer cell in tumor was statistically different. The proportion of CD8+ T cells in NSCLC, Colorectal cancer, Hepatobiliary cancer and others was 2.16%, 1%, 1.77% and 2.63%, p < 0.01; the proportion of natural killer cell was 16.44 %, 4.91%, 5.58% and 3.29%, p < 0.01. Conclusions: Different tumor types have different immune microenvironments. These results may provide valuable clues for future ICI trail design.

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