KEAP1 and lung carcinoma: In non-small cell lung cancer (NSCLC), the largest group of lung cancers, the expression of SSP enzymes has been reported to be highly heterogeneous in part due to up-regulation by nuclear factor erythroid 2-related factor 2 (NRF2), a target of the frequently mutated Kelch-like ECH-associated protein 1 (KEAP1) [22, 23].