Abstract 3459: Metabolomic profiling reveals significant differences between the ductal fluid from cancerous compared to unaffected breasts.

Abstract

Abstract Introduction: There is significant need to develop new methods to improve breast cancer (BC) screening and early detection. Metabolomic analysis of breast ductal fluid is an exciting opportunity for improving the detection of BC at an early stage. We hypothesize that differences between metabolomic profiles of tumor cells compared to normal cells can be used to develop an assay for early detection of BC. Breast ductal fluid can be obtained in a non-invasive way from the breast via nipple aspiration or ductal lavage. Approach: Metabolomic profiles were evaluated in ductal lavage fluid samples obtained from 54 patients with breast tumors (DCIS and Invasive Breast Cancer). The samples were collected in the operating room from patients with unilateral disease and confirmed diagnosis, prior to their surgery. For each patient, two samples were obtained: one from the affected breast and the other from the contralateral normal breast (control). Each patient served as her own control. Metabolite extraction was performed using a sequential solvent extraction protocol. Metabolomic analysis was performed using UPLC-TOF MS analysis and the data were acquired in duplicate (two technical replicates) for each sample. We used the XCMS package (Scripps Center for Metabolomics, La Jolla, CA) for peak detection, peak matching, and correction of retention time shift. This is followed by ion annotation to identify derivative ions originating from the same compound in the forms of adduct, isotopes, and in-source fragments. We performed statistical analysis to identify ions with significant difference between the tumor and normal samples. To correct for multiple testing, we used q-values based on Storey's pFDR method. Significant ions with q-value < 0.1 were selected. In addition, we calculated fold change (FC) based on the median of the relative intensity of tumor/normal samples for each pair. A subset of the significant ions with |FC| > 1.5 was selected. Putative identifications of the selected ions were obtained through mass-based search against four databases: the Human Metabolite DataBase (HMDB), Metlin, Madison Metabolomics Consortium Database (MMCD), and LIPID MAPS. Results: We analyzed the differences between normal and tumor samples excluding the subjects who received preoperative treatment (n=8). Based on statistical significance and FC, we selected 39 ions. Verification of putative IDs for these metabolites is underway. Conclusion: Our metabolomics analysis of the breast ductal fluid reveals significant differences between cancerous and normal breasts. These differences may be used to develop an assay that may improve early detection of BC. Supported by a Grant from the Avon Foundation for Women Citation Format: Luisa Matos do Canto, Shawna C. Willey, Elizabeth D. Feldman, Amrita Cheema, Mohammad R. Nezami Ranjbar, Habtom W. Ressom, Bassem R. Haddad. Metabolomic profiling reveals significant differences between the ductal fluid from cancerous compared to unaffected breasts. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3459. doi:10.1158/1538-7445.AM2013-3459