Several definitions for CA125 alterations in the monitoring of ovarian carcinoma treatment have been proposed including single measurement of CA125 values (Davelaar et al, 1996), relative percentage reduction in the CA125 level (Eisenhauer et al, 1994; Rustin et al, 1996, 1997, 2000; Bridgewater et al, 1999; Campos et al, 2001; Meyer et al, 2001; Dieras et al, 2002; Rustin, 2003), CA125 ratio at selected time intervals (Davelaar et al, 1996; de Jong et al, 1997) and exponential regression analysis of the CA125 levels (Yedema et al, 1993; Pearl et al, 1994; de Jong et al, 1997). This evidence concerns the gene MUC16 and ovarian carcinoma.