[Immune-Related Factors as Prognostic Markers for Resectable Colorectal Cancer]

Tumor infiltration of CD3 and CD8-positive T cells has been reported as a good prognostic marker for patients with colorectal cancer(CRC). To clarify the significance of CD4 and FOXP3-positive T cells in CRC for prognosis of intratumoral infiltration.CD3, CD8, CD4 and FOXP3-positive T cells were immunostained(IHC)from tissue specimens of 342 CRC patients who underwent curative resection to quantify the number of infiltrating cells in the tumor. Microsatellite instability(MSI)was also evaluated in 322 samples and the clinicopathological factors and survival were analyzed.Highly infiltrated groups of CD3, CD4 and FOXP3-positive T cells were associated with improved relapse-free survival(RFS). Highly infiltrated groups of CD8, CD4 and FOXP3-positive T cells were associated with improved disease- specific survival(DSS). Invasion depth, vascular infiltration, and CD4-positive T cell density were independent prognostic factors for DSS. CD4 and FOXP3-positive T cell infiltration was not associated with the high-frequency microsatellite instability group, in contrast to CD3 and CD8-positive T cell infiltration.Intratumoral CD4-positive T cell density and FOXP3-positive T cell densities were stronger prognostic indicators than other clinicopathological features. These results may facilitate the establishment of novel prognostic factors and therapeutic strategies for CRC.