TAM1_SPP1 in various tumor metastasis microenvironments shows consistent gene expression profiles (Figure 7C), including genes like LPL, FN1, SPARC, SDC2, FABP5, APOE, CD36, etc. However, TAM1_SPP1 is not a prominent subpopulation in the metastatic microenvironment of lung cancer and breast cancer (Figure 7A,B). This evidence concerns the gene APOE and breast cancer.