HMOX1 and lung carcinoma: Due to difficulties in obtaining sufficient human lung epithelial cells to perform this study, we chose the A549 cell line derived from a lung carcinoma due to its considerable use in the literature as a surrogate cell type24, 25, 26, 27 due to its high levels of glutathione28 and high (non-induced) heme oxygenase 1 (HO-1) gene expression levels29.