Downregulation of GYS1 significantly decreased cell growth of breast cancer cell lines BT474, SKBR3, MCF7, T47D, MDAMB453, MDAMB231, CAL51, MDAMB436, MDAMB468, HCC1143, HCC1937, HCC1806 (p<0.001, n=3) but not of SUM159PT. Here, GYS1 is linked to breast cancer.