Local radiotherapy increases the level of autoantibodies to ribosomal P0 protein but not to heat shock proteins, extracellular matrix molecules and EGFR/ErbB2 receptors in prostate cancer patients

Oncol Rep. 2013 Mar;29(3):1167-74. doi: 10.3892/or.2012.2197. Epub 2012 Dec 18.

Abstract

Prostate cancer is a common cancer among men in developed countries. Although hormonotherapy and radiotherapy (RT) represent valid therapies for prostate cancer treatment, novel immunological approaches have been explored. The development of clinical trials employing cancer vaccines has indicated that immune response to tumor antigens can be boosted and that vaccine administration can improve patient survival. Immune response to tumor antigens could also be enhanced after standard therapies. In the present study, we determined the occurrence of antibodies to extracellular matrix (ECM) molecules, heat shock protein (HSP), ribosomal P0 protein, EGFR, ErbB2 and prostate-specific antigen (PSA) in 35 prostate cancer patients prior to and following local RT and hormonotherapy. We demonstrated that immunity to P0, ECM molecules [collagens (C) CI, CIII, CV, fibronectin (FN) and laminin (LM)] and to HSP90 was associated with malignancy in untreated patients. None of the patient sera showed antibodies to EGFR, while 2 and 1 patients showed reactivity to ErbB2 and PSA, respectively. We also demonstrated that 8 months after therapy the IgG serum levels to CI, CIII, FN and HSP90 significantly decreased. Conversely, the level of P0 autoantibodies increased after therapy in 10 patients. Five of the 10 patients with increased levels of P0 autoantibodies were treated with RT plus hormonotherapy. Treatment of patients did not change the levels of antibodies against EGFR, ErbB2 and PSA. Our results indicated that the modification of antibody level to self molecules after standard treatment of prostate cancer patients is influenced by the type of antigen. Ribosomal P0 protein appears to be a high immunogenic antigen and its immunogenicity increases following RT. In addition, 10 patients with increased levels of autoantibodies to P0 showed PSA mean levels lower than the remaining 25 patients at 18 months. This study may contribute to a better understanding of the immunobiological behavior of prostate cancer patients following standard treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Autoantibodies / blood*
  • Case-Control Studies
  • ErbB Receptors / immunology*
  • Extracellular Matrix Proteins / immunology*
  • Heat-Shock Proteins / immunology*
  • Humans
  • Immunity, Humoral
  • Immunoglobulin G / blood
  • Kallikreins / immunology
  • Male
  • Middle Aged
  • Prostate-Specific Antigen / immunology
  • Prostatic Neoplasms / blood
  • Prostatic Neoplasms / immunology
  • Prostatic Neoplasms / radiotherapy*
  • Receptor, ErbB-2 / immunology*
  • Ribosomal Proteins / immunology*

Substances

  • Autoantibodies
  • Extracellular Matrix Proteins
  • Heat-Shock Proteins
  • Immunoglobulin G
  • Ribosomal Proteins
  • ribosomal protein P0
  • EGFR protein, human
  • ERBB2 protein, human
  • ErbB Receptors
  • Receptor, ErbB-2
  • KLK3 protein, human
  • Kallikreins
  • Prostate-Specific Antigen