J Cancer 2019; 10(22):5377-5387. doi:10.7150/jca.31787

Research Paper

Macrophages on the Peritoneum are involved in Gastric Cancer Peritoneal Metastasis

Hongjiang Song1,✉, Tie Wang1, Lining Tian2, Shuping Bai3, Li Chen1, Yanjiao Zuo1, Yingwei Xue1

1. Department of Gastrointestinal Surgery, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang Province, China
2. Department of Medical Education, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, China
3. Department of Internal Medical Oncology, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang Province, China

Abstract

Tumor-associated macrophages (TAM) have been shown to support tumor growth and progression by various mechanisms. However, the roles of TAM in gastric cancer (GC) peritoneal metastasis remain elusive. To explore the roles of macrophages in the process of GC peritoneal metastasis, we performed the present study. Samples from the primary GC tumor beds, surgical margins, peritoneal metastatic lesions and surrounding tissue, and the Pouch of Douglas, were collected, fixed by formalin, and embedded with paraffin. Immunohistochemistry staining for macrophages markers was performed. The peritoneal lavage was obtained from a fraction of patients to analyze the ratios of epidermal growth factor (EGF)- and vascular endothelial growth factor (VEGF)-secreting macrophages in the peritoneal cavity. GC patients with peritoneal metastasis had increased levels of macrophages and alternatively activated macrophages in the peritoneum compared to those without dissemination. Patients bearing more macrophages in the peritoneum had a poorer prognosis. GC patients bearing peritoneal metastasis harbored an increased level of angiogenesis. Macrophages in the peritoneal cavity were a source of EGF and VEGF.

Macrophages in the peritoneum of GC patients play a supportive role for peritoneal metastasis by producing EGF and VEGF. Macrophages in the peritoneum might be a therapeutic target in the future.

Keywords: gastric cancer, peritoneal metastasis, macrophages, tumor microenvironment

This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). See http://ivyspring.com/terms for full terms and conditions.
How to cite this article:
Song H, Wang T, Tian L, Bai S, Chen L, Zuo Y, Xue Y. Macrophages on the Peritoneum are involved in Gastric Cancer Peritoneal Metastasis. J Cancer 2019; 10(22):5377-5387. doi:10.7150/jca.31787. Available from http://www.jcancer.org/v10p5377.htm