Reduced SOD2 expression associates with chromosome 6 damage or deletion in some tumours, suggesting a tumour-suppressor function; defective SOD2 transcription associates with spontaneous tumourigenesis in inbred animals; tumour-associated defects in mitochondrial manganese transport reduce SOD2 activity; several tumour tissues and cell lines express low levels of SOD2; and SOD2 overexpression restores normal growth to some tumour cells [18], [32], [38], [39]. The gene discussed is SOD2; the disease is neoplasm.