Detailed analysis of inflammatory cell infiltration in colorectal cancer

Background: Higher-grade inflammatory infiltrate is a promising marker for better prognosis in colorectal cancer (CRC). However, the knowledge on the interrelationships between different inflammatory cells and classifications is fragmentary. Methods: We analysed the densities of eight types of inflammatory cells in a prospectively recruited group of 117 CRC patients and determined their interrelationships and contributions to Klintrup-Makinen (K-M) score of overall peritumoural inflammation. We characterised the inflammatory infiltrate in relation to stage and recurrences in 24-month follow-up. Results: There were high positive correlations between the inflammatory cell densities, with the exception of mast cells and CD1a(+) immature dendritic cells. High K-M score associated with high peri-and intratumoural densities of CD3(+), CD8+, CD68(+), CD83+, and FoxP3(+) cells and neutrophils. Advanced stage associated with low K-M score, as well as low CD3(+), CD8+, CD83(+), and FoxP3(+) cell counts, of which low K-M score, low CD3(+) T-cell count, and low FoxP3(+) T-cell count were linked to higher recurrence rate. Conclusion: The density of CRC inflammatory infiltrate declines as stage advances. Especially, low K-M score and low T-cell counts predict higher recurrence rate. The high positive correlations between the individual inflammatory markers support the value of overall inflammatory reaction scoring.