SP1 and adenocarcinoma: Although SOD3 promoter region is incompletely analyzed, it has been demonstrated that CpG methylation downregulates Sp1/Sp3 transcription factor binding to putative promoter region inhibiting SOD3 promoter activity and mRNA synthesis in vitro in human A549 adenocarcinoma lung alveolar basal epithelial cells [37] thus being in line with the current data.