Because phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) are important in the regulation of survival in human ovarian cancer cells (Mills et al, 2001; Choi et al, 2003), we tested whether PI3K and MAPK are involved in MnSOD siRNA-mediated chemosensitisation. The gene discussed is SOD2; the disease is ovarian carcinoma.