title: Differentiating tumor heterogeneity in formalin-fixed paraffin-embedded (FFPE) prostate adenocarcinoma tissues using principal component analysis of matrix-assisted laser desorption/ionization imaging mass spectral data.
abstract: BACKGROUND
  Many patients with adenocarcinoma of the prostate present with advanced and metastatic cancer at the time of diagnosis. There is an urgent need to detect biomarkers that will improve the diagnosis and prognosis of this disease. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) is playing a key role in cancer research and it can be useful to unravel the molecular profile of prostate cancer biopsies.
  
  
  METHODS
  MALDI imaging data sets are highly complex and their interpretation requires the use of multivariate statistical methods. In this study, MALDI-IMS technology, sequential principal component analysis (PCA) and two-dimensional (2-D) peak distribution tests were employed to investigate tumor heterogeneity in formalin-fixed paraffin-embedded (FFPE) prostate cancer biopsies.
  
  
  RESULTS
  Multivariate statistics revealed a number of mass ion peaks obtained from different tumor regions that were distinguishable from the adjacent normal regions within a given specimen. These ion peaks have been used to generate ion images and visualize the difference between tumor and normal regions. Mass peaks at m/z 3370, 3441, 3447 and 3707 exhibited stronger ion signals in the tumor regions.
  
  
  CONCLUSIONS
  This study reports statistically significant mass ion peaks unique to tumor regions in adenocarcinoma of the prostate and adds to the clinical utility of MALDI-IMS for analysis of FFPE tissue at a molecular level that supersedes all other standard histopathologic techniques for diagnostic purposes used in the current clinical practice. Copyright © 2016 John Wiley & Sons, Ltd.
authors: Brown University, Warren Alpert Medical School, COBRE Center for Cancer Research, Rhode Island Hospital, Providence, RI, USA.|National and Kapodistrian University of Athens, Department of Pharmacy, Division of Pharmaceutical Chemistry, Laboratory of Pharmaceutical Analysis, Athens, Greece.
authors: Irene
authors: I
authors: Panderi
authors: Brown University, Warren Alpert Medical School, Department of Pathology, Rhode Island Hospital, Providence, RI, USA.
authors: Evgeny
authors: E
authors: Yakirevich
authors: University of Michigan Comprehensive Cancer Center, School of Medicine, Department of Periodontics and Oral Medicine, Division of Oral Pathology/Medicine/Radiology, Ann Arbor, MI, USA.
authors: Silvana
authors: S
authors: Papagerakis
authors: Brown University, Warren Alpert Medical School, COBRE Center for Cancer Research, Rhode Island Hospital, Providence, RI, USA.
authors: Lelia
authors: L
authors: Noble
authors: Brown University, Warren Alpert Medical School, Department of Pathology, Rhode Island Hospital, Providence, RI, USA.
authors: Kara
authors: K
authors: Lombardo
authors: Brown University, Warren Alpert Medical School, COBRE Center for Cancer Research, Rhode Island Hospital, Providence, RI, USA.|Weill Cornell Medical College, Division of Infectious Diseases, Transplantation-Oncology Infectious Disease Program, New York, NY, USA.
authors: Dionysios
authors: D
authors: Pantazatos
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000145:classification; D014408:Biomarkers, Tumor / Q000032:analysis*; D005557:Formaldehyde; D006801:Humans; D008297:Male; D016612:Paraffin Embedding; D025341:Principal Component Analysis; D011467:Prostate / Q000737:chemistry*; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000145:classification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor; D005557:Formaldehyde