NFE2L2 and breast cancer: Aside from the cell lines mentioned above, at present, arsenicals also have been shown to activate the NRF2 pathway in placental choriocarcinoma cells [20], HeLa [21], myeloma cells [22], and breast cancer cells (MDA-MB-231) [23], indicating arsenic could induce the activation of NRF2 pathway in various cell types, and NRF2 pathway plays an extremely pivotal role in protection against arsenic-mediated toxicity in vitro.