Molecular portrait of prostate tissue probed by MALDI Imaging Mass Spectrometry

Benign prostatic hyperplasia (BPH) is the most common condition in aging men, associated with lower urinary tract symptoms. BPH has been suggested to be a risk factor for certain urologic cancers, but the current evidence is inconsistent. The gold-standard method for the diagnosis of BPH is histopathology. Histopathology displays the cellular morphologies of tissues wherein characteristic changes pertaining specifically to BPH can be identified. However, the onset of BPH might be associated with minimal phenotypic changes in cellular morphologies in tissues that histopathology might not be able to detect successfully. Therefore, to understand the onset of a disease and its pathogenesis it is important to investigate the detailed molecular profiles associated with the disease that might help in the diagnosis and to understand the insights of the disease pathogenesis. Over the last decade, imaging mass spectrometry has been used to explore the spatial distribution and expression profiles of several molecules with their two-dimensional heterogeneity retained across the tissues. In the present study, using MALDI mass spectrometry based tissue imaging platform, we observed the expression of several proteins across human prostate tissue sections diagnosed with BPH. The proteins were identified and characterized using tissue proteomics approach. We could successfully identify the on-tissue distribution of ribonuclease T2, vinculin, isoform 2 of tropomyosin alpha-3 chain and mitochondrial citrate synthase proteins using this approach. Therefore, imaging mass spectrometry might be a potential tool to complement the findings of histopathology in diagnosis of BPH in human prostate tissues.