To further assess the impact of mut-p53 on SPAG5 expression, we knocked it down in four BC cell lines harboring different TP53 missense mutations: MDA-MB-468 (R273H), MDA-MB-231(R280K), SUM-159 (R158L) TNBC cell lines, and SKBR3 (R175H) HER-2 positive BC cells. This evidence concerns the gene SPAG5 and breast cancer.