Interleukin-6-Positive Immune Cells as a Possible New Immunologic Marker Associated With the Colorectal Cancer...

Area of Science:

• Oncology
• Immunology
• Genetics

Background:

• Chronic inflammation drives colorectal cancer (CRC) progression by creating a tumor microenvironment (TME).
• Interleukin-6 (IL-6), a pro-inflammatory cytokine, plays a multifaceted role in CRC development.
• Understanding IL-6's expression and genetic variations is crucial for deciphering CRC mechanisms.

Purpose of the Study:

• To evaluate IL-6 expression in tumor and immune cells within the TME of CRC patients.
• To assess serum IL-6 levels and the IL6 -174 G/C genotype distribution.
• To correlate these findings with clinicopathologic parameters for insights into CRC progression.

Main Methods:

• Quantified serum IL-6 using ELISA in 153 CRC patients and controls.
• Assessed IL-6 expression in tumor and immune cells via immunohistochemistry and immunofluorescence.
• Determined microsatellite instability (MSI) status and IL6 -174 G/C genotype using PCR-RFLP.

Main Results:

• CRC patients exhibited elevated serum IL-6 levels compared to healthy controls (P<0.0001).
• Increased IL-6+ immune cells were found in the invasive front (IF) versus tumor stroma (TS) (P<0.0001).
• Higher IL-6+ cell levels, especially in the IF, correlated with less advanced tumor types, early stages, and longer patient survival (P=0.012).

Conclusions:

• Elevated serum IL-6 in CRC patients, while associated with advanced histologic types, shows a borderline association with longer survival.
• Increased IL-6+ immune cells in the TME, particularly at the invasive front, are linked to favorable prognostic variables and improved survival in early-stage CRC.