SPHK1 and cancer: High expression of APOL1 in the tumor microenvironment indicated that it played an important role in tumor invasion and immune defense 49 (Figure 5C); T cells displayed a high expression level of IFNG, mediating T cell killing to suppress tumors in immune regulation 50 (Figure 5D); SPHK1 was highly expressed in epithelial cells and fibroblasts, which might regulate fibroblast differentiation to promote cancer proliferation 51-54 (Figure 5E).