Purpose

To search for potential protein markers or activated pathways which play a role in ovarian cancer.

Experimental procedures

Serum of six patients with a serous adenocarcinoma of the ovary (stage IIIB or higher) was collected before treatment. Matched control patients with a serous cystadenoma of the ovary were chosen as a control group. In addition, homogeneous regions of cells that exhibited uniform histology were isolated from cancer tissue in three of these patients by laser capture microdissection (LCM), normal ovarian epithelial cell samples were taken from their matched controls. Subsequently we employed label-free liquid chromatography tandem mass spectrometry (LC-MSE) to identify proteins and determine their absolute concentrations in serum specimens and tissue lysates. Moderated t-tests were used to identify differentially expressed proteins between patient- and control-group, p-values were adjusted for multiple-testing using Benjamini-Hochberg false discovery rates. Proteins were considered to be differentially expressed if the adjusted p-values were <0.05.

Summary of the data

In the serum specimens, 13 differentially expressed proteins were identified by LC-MSE profiling. Proteins with different concentrations in patients versus control sera include abundant serum proteins such as apolipoprotein AI and transferrin, that both exhibited a lower concentration in serum of cancer patients. Differential expression was also observed for apolipoproteins (APOA IV, APOA II and APOC III) and other proteins that have not been associated with ovarian cancer previously such as C9 and Afamin.

In the tissue lysates, 17 differentially expressed proteins were identified. Amounts of collagen found were decreased in cancer tissue. Furthermore, proteins associated with the respiratory chain and cell migration were found in increased amounts in the cancer tissue lysates.

Interestingly, no overlap was found between the discriminatory proteins in serum specimens and corresponding tissue lysates, illustrating the challenge to identify a single biomarker in the circulation reflecting ovary cancer.

Conclusions

Our study revealed several protein changes in serum and the ovary of patients suffering from serous adenocarcinoma of the ovary (stage IIIB or higher). Further investigation of these proteins is warranted to establish whether they could provide new insights into the etiology of the disease and act as potential new disease markers.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3980.