In our study, which analyzed the association between immune-related genes and Sphk1 gene expression in breast cancer using the Cancer Genome Atlas database, breast cancers with high Sphk1 expression are associated with increased expression of immune-related genes, such as CD68, CD163, CD4, and forkhead box protein 3, which are associated with increased myeloid-derived suppressor cells (MDSCs), and Treg infiltration is suggested to be increased [203]. The gene discussed is CD4; the disease is breast cancer.