CD4 and type 2 diabetes mellitus: Subsequently, we analyzed the relationship between the expression levels of the three genes and the infiltration levels of each immune cell type in both disease samples (Supplementary Fig. S2).Our findings were as follows: In type 2 diabetes mellitus and colorectal cancer, the following patterns were observed: Firstly, the expression of FABP4 was negatively correlated with the infiltration of neutrophils, Th2 cells, Th17 cells, CD4 + T cells, and NK cells, while it was positively correlated with the infiltration of the remaining immune cells (Fig. 6A,B).