Ovarian cancer and liquid chromatography/ mass spectrometry of molecular markers of predisposition and early-stage disease

In Austria, 1000 women are affected every year by ovarian cancer, which is statistically 1.4 women out of 100. Due to the lack of early symptoms, ovarian cancer is typically diagnosed at a late clinical stage with a 5-year survival rate of only 35%. Identification of genetic factors that increase predisposition to ovarian cancer has made great progress, but most predisposing alleles show only incomplete penetrance. Beside the identificaion of mutations, there is a tremendous need to develop new technologies for early detection of ovarian cancer because todays most used biomarker CA125 in combination with ultrasound yields a predictive value of only 35%. Two major project aims are proposed: First, improvement of the mutation detection sensitivity of denaturing high- performance liquid chromatography (DHPLC), which is already widely used for mutation screening of BRCA1 and BRCA2. The application of mass spectrometry instead of conventional UV detection should improve sensitivity from currently >95% to nearly 100% and increase the information content of DHPLC by determinng the chemical nature of a mutation based on characteristic mass differences between the four bases of the genetic code. The second aim is the refinement of a recently presented method for the early-stage detection of ovarian cancer, which uses a combination of solid-phase extraction and matrix-assisted laser desorption and ionisation time-of- flight (MALDI-TOF) mass spectrometry to generate profiles of low molecular-weight serum proteins that carry a positive predictive value of 94% for ovarian cancer. The refinement will include the use of HPLC to obtain fractionation and purification of ovarian cancer specific proteins for further characterization, and the application of electrospray ionisation mass spectrometry to improve mass accuracy. The experimental approach should be of general utility in the identification of serum profiles characteristic for other types of cancer.