Nrf2 expression refers to the regulation and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor. Nrf2 is a key regulator of cellular defense mechanisms against oxidative stress and inflammation. When cells are exposed to oxidative stress, Nrf2 is activated and translocates into the nucleus where it binds to antioxidant response elements (AREs) in the promoter regions of target genes, leading to the transcription of various antioxidant and detoxifying enzymes. Research into Nrf2 expression involves studying the mechanisms that regulate Nrf2 activation, its role in protecting cells from oxidative damage and inflammatory responses, and its potential therapeutic implications for various diseases such as cancer, neurodegenerative disorders, and cardiovascular diseases. Understanding Nrf2 expression and its downstream effects can provide insights into novel therapeutic strategies for combating oxidative stress-related diseases.