E2F-1 transcription factor immunoexpression is inversely associated with tumor growth in colon adenocarcinomas

Anticancer Res. 2004 Sep-Oct;24(5A):3041-7.

Abstract

E2F-1 is an intriguing transcription factor that accumulates the integrated signal of the G1-S transition regulators. Its role in cell fate, as depicted from in vivo models and a few studies on human tissues, is a matter of debate, since it confers a tissue-specific oncogenic or tumor suppressor behavior. In the present work, in an attempt to shed light on the role of E2F-1 in colon cancer, we examined E2F-1 expression in a series of 45 colon carcinomas and we further correlated it with tumor kinetics. E2F-1 expression and proliferation were evaluated by immunohistochemistry as the percentage of E2F-1 (E2F-1 index: EI) and Ki-67 (Proliferation index: PI)-positive cells, respectively; whereas apoptosis was estimated as the percentage of positive, by TUNEL assay, cells (Apoptotic index: AI). The relationship between E2F-1 expression and tumor kinetics was assessed by microscopical evaluation in semi-serial tissue sections and statistical analysis. Our results demonstrated that E2F-1 expression was inversely correlated with tumor growth (GI=PI/AI) (p=0.002). Specifically, the histological observations showed that E2F-1 was expressed in lesions with high apoptotic incidence and low proliferation. These results also supported the statistical findings showing that EI was inversely correlated with PI (p < 0.001) and positively associated with AI (p = 0.013). In conclusion, we suggest a tumor-suppressive behavior of E2F-1 in colon carcinomas.

MeSH terms

  • Adenocarcinoma / immunology
  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / pathology*
  • Cell Cycle Proteins / biosynthesis*
  • Cell Cycle Proteins / immunology
  • Cell Growth Processes / physiology
  • Colonic Neoplasms / immunology
  • Colonic Neoplasms / metabolism*
  • Colonic Neoplasms / pathology*
  • DNA-Binding Proteins / biosynthesis*
  • DNA-Binding Proteins / immunology
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • Humans
  • Immunohistochemistry
  • Neoplasm Staging
  • Transcription Factors / biosynthesis*
  • Transcription Factors / immunology

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • Transcription Factors