Screening Serum Biomarkers Of Ovarian Cancer By Serum Peptidome Pattern

Background:Ovarian cancer is neither a common nor a rare disease,but it was the leading cause of death of gynecologic malignant neoplasma.As with no specific symptorns in early stage(FIGOⅠ-Ⅱ),over 70%Ovarian cancer were diagnosed in advanced stage. Most women diagnosed with ovarian cancer were postmenopausal.Recent decades, there were many progression in surgical treatment and chemotherapy in ovarian cancer therapy,5 year survival rate of ovarian cancer with advanced stage(FIGOⅢ-Ⅳ) is remain about 30%.But 5 year survival rate of early stage could reach 90%, compare with the 30%of advanced,widespread disease.Searching early detection pattern is the key to prolong survival,reduce cost of treatment,improve the quality of life.B iomarker is the important means for early diagnosis of ovarian cancer.The CA125 is an epitope on a large mucin glycoprotein molecule of greater than 1 million Daltons,normal expressed on the coelomic epithelium,including ovarian surface.By now,CA125 assay has been used for monitoring response to primary treatment,detecting clinically occult ovarian cancer at the time of recurrence,as well detecting primary disease in early stage.The CA125 level is abnormal in over 90%of advanced stage ovarian cancer,but it is not increased in about 50%of the patients with stageⅠdisease.CA125 has a positive predictive value of less than 10%as single marker,not reach the need of the specificity for screen according to the relative lower incidence rate of ovarian cancer in 40/100,000.The new biomarkers with high sensitivity and specificity are urgently needed for ovarian cancer screen.Mass spectrum is a power tools in mapping and identifying new proteins.The Clinprot^TM system based on MALDI-TOF MS is a new high throughput liquid-protein chip system with high sensitivity,by using magnetic beads to pure and enriches target protein/peptides.CIinprot^TM system becomes a valuable tool in screening new biomarker of ovarian cancer.Methods:All serum samples were obtained from department of obstetrics and gynecology, PLA General Hospital,from Mar 2007 to Nov 2008.Serum samples from 70 ovarian cancer patients(FIGO stageⅠ-Ⅳ) were collected before surgery or chemotherapy. All patients were surgically staged.The nondisease serum samples were collected from 59 women in Healthy Medical Center of PLA General Hospital without any evidence of cancer as healthy controls.52 ovarian cancer patients and 44 health controls were set in training set,18 ovarian cancer patients and 15 health controls were set in validation set.Cuprum chelate magnetic beads kit synthesized by National Biomedical Analytic Center was choose to concentrate the potential biomarkers in low abundant protein of serum.The steady Clinprot system was established through validating the reproducibility.Serum peptidomee pattern were obtained by MALDI-TOF-MS(Matrix-Assisted Laser Desorption-Ionization Time-of-flight mass spectrum).Data from training set were analyzed by the bioinformatics software Clinprotools 2.1 to establish diagnostic model of ovarian cancer.Then,the accuracy of the model was validated by using classification validation and cross validation.Results:The peak intensity coefficient of variability(CV) of the within day,day by day and repeated freeze thawing reproducibility were all less 27%,according with international accepted CV＜30%.There was no significant difference in different age class of women.Analyzed by Clinprotools 2.1 software,25 peaks were obtained to compose the diagnostic model,in the range of m/z 1000-10,000.Among the 25 peaks, 12 were up regulated and 13 were down regulated in ovarian cancer group.The software got the 100%sensitivity and 96.67%specificity in training set.Cross validation showed the 100%sensitivity and 93.3%specificity in validation set.ConclusionThe magnetic bead separation and MALDI-TOF analysis in combination with bioinformatics software(Clinprot^TM system) is useful for the high-throughput cancer research.The discovered model with high specificity and sensitivity could separate ovarian cancer from healthy control correctly.After identified,Protein/peptide discovered by Clinprot system would be good biomarkers for ovarian cancer screening.