Expression of p53 gene product and cell proliferation marker Ki-67 in Ewing’s sarcoma: Correlation with clinical outcome

Gail Amir, Josephine Issakov, Isaac Meller, Erwin Sucher, Amos Peyser, Ian J. Cohen, Isaac Yaniv, Myrian Weyl Ben Arush, Uri Tavori, Yehuda Kollender, Noemi Ron, Nili Peylan-Ramu

Research output: Contribution to journalArticlepeer-review

Abstract

Overexpression of tumor suppressor gene p53, cell proliferation nuclear antigen Ki-67, and proto-oncogene HER-2/neu are associated with poor prognosis in some tumors. We studied p53, Ki-67, and HER-2/neu immunohistochemical expression in archival biopsies of 37 patients with Ewing's sarcoma (ES). Patients with ES were treated at four Israeli hospitals between 1982 and 2000. Formalin -fixed paraffin-embedded tissue sections were stained by immunohistochemistry for p53, Ki-67, and HER-2/neu. More than 300 cells were counted on each slide, and the percentage of positively stained nuclei was computed. p53 overexpression was defined as nuclear staining of >2.3% of cells, Ki-67 overexpression as nuclear staining of >8.3% malignant cells. HER-2/neu staining was scored semiquantitatively on a scale of 0 to 4+. Twenty-two of 37 patients are alive and well, with mean follow-up time of 38 months. There was overexpression of p53 in 16 patients (43%) and of Ki-67 in 21 patients (57%). The correlation between p53 and Ki-67 overexpressions was 0.61. We found no overexpression of HER-2/neu. Median relapse-free survival (RFS) was statistically significantly shorter for patients with p53 overexpression (25 months) than for patients with negative staining (>92 months). The prognostic value of p53 overexpression was also significant after adjusting for tumor location and age. Median RFS was shorter for patients with positive Ki-67 staining (40 months) than for patients with negative staining (80 months) but did not reach statistical significance. Our study suggests that p53 is a predictor of RFS in patients with ES. More patients must be studied to assess the validity of this observation.

Original languageEnglish
Pages (from-to)170-174
Number of pages5
JournalHuman Pathology
Volume33
Issue number2
DOIs
StatePublished - Feb 2002

Keywords

  • Ewing's sarcoma
  • HER-2/neu
  • Ki-67
  • p53

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