Perineural Invasion or Neurogenesis?
Ana Maria Cano-Valdez, Nelly Cruz-Viruel, Hugo Dominguez-Malagon. Instituto Nacional de Cancerologia, Mexico City, Mexico; Hospital Juarez de Mexico, Mexico City, Mexico
Background: BACKGROUND. Perineural invasion (PNI) is a common phenomenon frequently observed in carcinomas of several organs and in some tumors is considered a prognostic factor for recurrence after surgical treatment. Together with PNI we have frequently observed nerve hypertrophy (NH). That 's why we postulate that nerve fibers may be produced in situ or their growth may be stimulated by neoplastic factors that induce nerve proliferation and hypertrophy. To investigate this possibility, we examined the size of nerve fibers and the expression of diverse growth factors and nerve markers in a group of carcinomas with PNI.
Design: METHODS. Thirty six cases of carcinomas with PNI and nerve fiber hypertrophy (NH) were collected (Group I), and compared with 23 cases neither PNI nor NH (Group II). The paraffin blocks were selected and tissue microarrays were performed. Immunohistochemical studies were done on tissue macroarrays (“microchops”) using antibodies against: low-affinity nerve growth receptor p75NTR (CD56), S-100 protein, platelet derived growth factor receptor (PDGFR) and epithelial growth factor receptor (EGFR). Comparative analysis of expression in both groups and the presence of NH were done and statistical analysis was performed using student T test.
Results: RESULTS. NH and PNI were easily seen on routine slides in all cases of Group I, while only 3 cases of Group II showed H&E visible nerve fibers, and they required S-100 protein to highlight them. Average nerve size was 0.23cm in group I, whereas 0.018cm nerve thick was observed in control group. A greater NGFR expression was observed in group I (47% vs 23%). However, statistical difference wasn't significant. No differences were found with S100, PDGF and EGFR.
Conclusions: CONCLUSIONS. Our findings don't support the neurogenesis theory. However, use of therapies directed against tumoral neurotrophins as potential molecular targets may be useful to limit recurrence, dissemination and in consequence, to improve survival. Nevertheless, it is necessary to carry out more studies analyzing other factors of nervous growth to support this theory.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 245, Wednesday Morning