HMOX1 and neoplasm: To investigate correlations between the expression of MKP-1, Nrf2, and the Nrf2 target gene HO-1 in NSCLC cells, we assessed their immunohistochemical status in sections of tumor samples from 95 lung adenocarcinomas, of which >90% were moderately- or poorly-differentiated (Table 1 and Figure 6).