Though the frequency of Tregs (CD45+ CD3+ CD11b- CD4+ CD8- CD25+ Foxp3+) was also higher in CT-26 tumor tissues, (Fig. 2G), the ratio of CD8 to Treg in CT-26 tumor tissues was significantly higher than that in Colon 26 tumor tissues (Fig. 2H). Here, CD4 is linked to neoplasm.