Even basal levels of cGMP, generated primarily by basal sGC activity, and subsequent partial activation of PKG are sufficient (in fact, necessary) to prevent spontaneous apoptosis in certain cells, including NG108-15 cells (Fiscus, 2002; Fiscus et al, 2002), immortalised uterine epithelial cells (Chan and Fiscus, 2003), and human ovarian cancer cells (Fraser et al, 2006). This evidence concerns the gene SGCB and ovarian carcinoma.