Nuclear factor (erythroid-2)–related factor 2(Nrf2) expression in gastric carcinoma cell lines. Nrf2 protein expression in nuclear and cytoplasmic extracts of the gastric cell lines MKN74, MNK45, KATO-III, and NUGC4 was assayed by Western blotting. The blot was re-probed with anti-Lamin B1 and anti-α-Tubulin antibodies that were used as positive controls for the nucleus and cytoplasm, respectively. Nuclear and cytoplasmic fractions were clearly separated. The Nrf2 protein was identified mainly in the nucleus of all gastric cancer cell lines. Little Nrf2 was detected in the cytoplasm.