Pseudomyxoma peritonei: inflammatory responses in the peritoneal microenvironment

Area of Science:

• Oncology
• Immunology
• Gastroenterology

Background:

• Pseudomyxoma peritonei (PMP) is a rare appendiceal neoplasm characterized by peritoneal mucinous carcinomatosis.
• Inflammation and fibrosis are integral to PMP biology, but the role of the tumor microenvironment remains underexplored.

Purpose of the Study:

• To characterize the cytokine and C-reactive protein (CRP) profiles in PMP.
• To investigate the relationship between serum and ascites levels of these markers.
• To identify potential serum biomarkers and therapeutic targets for PMP.

Main Methods:

• Immunoassays were used to quantify 42 cytokines and CRP in ascites, peritoneal washings, and serum samples from PMP patients.
• Immunohistochemistry was employed to localize cytokine expression within tumor tissues.
• Statistical analyses included Wilcoxon signed rank test, Mann-Whitney U-test, and bivariate analysis.

Main Results:

• Serum CRP levels were elevated in PMP patients and correlated with ascites CRP.
• Ascites showed significantly elevated levels of interleukin-6 (IL-6), IL-8, IP-10, MCP-1, and MIP-1α, but these did not correlate with serum levels.
• IL-6 was localized to the stroma, IP-10 and MCP-1 to tumor cells, and IL-8 to adipose tissue, indicating specific cellular sources.

Conclusions:

• The PMP inflammatory cytokine profile differs from infection or injury-associated inflammation, suggesting peritoneal synthesis.
• Serum CRP, IL-8, and MIP-1β are identified as potential diagnostic markers for PMP.
• IL-6 plays a critical role in PMP pathogenesis, presenting a potential therapeutic target.