In light of the negative correlation between the expression level of TTK and the survival period of patients with BC, we verified the high expression and prognostic value of TTK in BC through GEPIA, GSE13507, and GES32894 (p < 0.05; Figures 7A–C) and used the median expression of TTK in the BC samples of TCGA as the cutoff point; samples with high and low expressions of TTK were analyzed using GSEA. This evidence concerns the gene TTK and breast cancer.