Inflammatory cells and pancreatic tumor progression

Introduction: Pancreatic adenocarcinoma remains one of the deadliest cancers. Many years of research have improved neither treatment nor diagnosis of this devastating disease. Infiltrating inflammatory cells might be part of the antitumor response but also they may take part in supporting tumor invasion. In particular, macrophages and neutrophils were shown to present pro-tumor phenotype.

Aim: To define the inflammatory microenvironment within the pancreatic tumor and how it influences tumor progression and the ability to create metastases.

Material and methods: Pancreatic tumor tissue samples were collected from 36 patients diagnosed with pancreatic cancer. Tumor tissue was analyzed using immunohistochemistry. Staining against CD68, CD3, CD56 and neutrophil elastase was performed and evaluated using MicroImage software.

Results: We observed numerous infiltrates of lymphocytes and macrophages. Neutrophils were also present but no NK cells were observed. Inflammatory cells were present around neoplastic glands and also strongly around nerves infiltrated by cancer cells. We found that the number of infiltrating macrophages was significantly higher in the group of patients with lymph node metastases and in tumors with perineural invasion.

Conclusions: There is no doubt that infiltrating tumor cells are a pivotal element of the pancreatic tumor microenvironment. In particular, macrophages take part in tumor progression and enable creation of metastases. Investigating infiltrating macrophages might be useful in evaluating the possibility of metastases occurrence.