Metabolites and Histology on Exactly the Same Biopsy Tissue
Dean A Troyer, Jeffrey R Shuster, Raymond Lance. Eastern Virginia Medical School, Norfolk, VA; Biomarker Factory, Durham, NC
Background: An increasing number of molecular biomarker assays are performed that frequently compete with histopathology for the same tissue. Small molecule metabolites are increasingly recognized as potential biomarkers of cancer and other diseases. We have developed a method to assay metabolites and perform histology on the exact same tissue called molecular preservation by extraction and fixation (mPREF).
Design: 18 gauge core-needle biopsies taken ex vivo from human prostatectomy samples were immediately placed in 1 mL of 80% aqueous methanol. After 12-24 hours, biopsy cores were transferred to formalin and processed by standard histologic methods. The methanol is retained for metabolite analysis. From more than 200 small molecules identified on a metabolomics platform, we have selected nine for quantification by liquid chromatography/mass spectroscopy (LC/MS): betaine, malate, proline, N-acetylaspartate, uracil, xanthine, cysteine, and alanine. The molecules were chosen in part because their physical and chemical properties allows them to be run on a single LC/MS run.
Results: Preliminary results showed trends in tumor vs. no tumor for betaine, proline, uracil, cysteine, and N-acetylglucosamine when normalized to the biopsy surface area. Shown in the attached table are results for a total of 15 normal/tumor pairs.
|Metabolite||No Tumor µM/cm2||Tumor µM/cm2|