Conversely, mitochondrial glutamate carrier 2 was found to be causally associated with ER-breast cancer as a risk factor (IVW, p=0.049, OR = 1.083, 95% CI: 1.000–1.174), along with mitochondrial sodium/hydrogen exchanger 9B2 which was identified as a risk factor for ER-breast cancer (IVW, p=0.031, OR = 1.074, 95% CI: 1.006–1.145). The gene discussed is SLC9B2; the disease is breast cancer.