ERBB2 and breast cancer: There was no significant association for HER2-overexpressing BC (RR: 0.92, 95% CI: 0.79, 1.07, I2 = 17.7%, p = 0.225) or TNBC (RR: 1.03, 95% CI: 0.93, 1.15, I2 = 21.0%, p = 0.165).