OBJECTIVETo find new serum tumor markers for ovarian epithelial cancers by 2-DE DIGE and MALDI-TOF/TOF proteomic methods, in order to improve the diagnostic sensitivity and specificity.

METHODSSerum samples from 103 cases of ovarian epithelial cancers, 60 cases of healthy women, 63 cases of benign ovarian tumors and 63 cases of benign pelvic diseases were collected. Sera of 20 cases of ovarian epithelial cancers (A), 20 cases of ovarian benign tumors (B), 20 cases of pelvic benign diseases (C) and 20 cases of health control (D) were matched by age and pooled, respectively. After depletion of high abundance serum albumin and IgG, the samples were assayed by 2-DE DIGE. The test was repeated three times. Analysis with DeCyder software revealed significant differential protein spots which were identified by MAIDI-TOF/TOF. Western blot and ELISA were used to validate the candidate serum markers.

RESULTS1) There were 41 proteins having significant differences between the groups. MAIDI-TOF/TOF successfully identified 28 proteins. Haptoglobin (Hp) was the most significantly up-regulated protein, and transferrin (Tf) was the most significantly down-regulated protein. 2) Western blot and ELISA proved that there were significant differences in Hp and Tf between ovarian epithelial cancers and normal controls (P = 0.000), between ovarian epithelial cancers and ovarian benign tumors (P = 0.000), between ovarian epithelial cancers and benign pelvic disease sera (P = 0.000). 3) CA125 + Hp + Tf combined detection of ovarian cancer had higher sensitivity and specificity than CA125, Hp or Tf detection alone.

CONCLUSIONHp and Tf are differently expressed in the sera of patients with ovarian epitheliual cancers. They can be used as serum biomarkers for ovarian epithelial cancers. CA125 + Hp + Tf combined detection may improve the sensitivity and specificity of diagnosis of ovarian epithelial cancers.