Introducing the MUC16 gene: implications for prevention and early detection in epithelial ovarian cancer

More than 24,000 women in the United States are diagnosed with ovarian cancer every year, and half of these women die from their disease. Stage 1 ovarian cancer is curable in 95% of cases; however, due to inadequate screening tools and lack of symptoms in early disease, ovarian cancer is generally at Stage 3 or 4 when finally diagnosed. CA125 is a tumor antigen used to monitor the progression and regression of epithelial ovarian cancer. When its levels are elevated postsurgery (hysterectomy/salpingo-oophorectomy with or without peritoneal washings and lymph node biopsy) and postchemotherapy, it is suggestive of recurrent disease. Due to its similarly elevated levels in some nonmalignant conditions, however, it is not specific enough to be used for population screening. The CA125 molecule is considered a very large glycoprotein because of its molecular weight, and it has three domains: the carboxy terminal domain, the extracellular domain, and the amino terminal domain. MUC16 is the gene that encodes the peptide moiety of the CA125 molecule. MUC16 domains provide novel opportunities to develop new assays and refine current tools to improve the sensitivity and specificity of CA125 for population-based screening guidelines.