PLoS ONE (Jan 2017)

Evaluation of the proliferation marker Ki-67 in a large prostatectomy cohort.

  • Elin Richardsen,
  • Sigve Andersen,
  • Samer Al-Saad,
  • Mehrdad Rakaee,
  • Yngve Nordby,
  • Mona Irene Pedersen,
  • Nora Ness,
  • Thea Grindstad,
  • Ingeborg Movik,
  • Tom Dønnem,
  • Roy Bremnes,
  • Lill-Tove Busund

DOI
https://doi.org/10.1371/journal.pone.0186852
Journal volume & issue
Vol. 12, no. 11
p. e0186852

Abstract

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The tumor proliferation index marker Ki-67 is strongly associated with tumor cell proliferation, growth and progression, and is widely used in routine clinicopathological investigation. Prostate cancer is a complex multifaceted and biologically heterogeneous disease, and overtreatment of localized, low volume indolent tumors, is evident. Here, we aimed to assess Ki-67 expression and related outcomes of 535 patients treated with radical prostatectomy. The percentage of tumor epithelial cells expressing Ki-67 was determined by immunohistochemical assay, both digital image analysis and visual scoring by light microscope were used for quantification. The association of Ki-67 and prostate cancer was evaluated, as well as its prognostic value. There was a positive correlation between high expression of Ki-67 and Gleason score > 7 (p < 0.001) as well as tumor size (≥ 20 mm, p = 0.03). In univariate analyses, a high expression of Ki-67 in tumor epithelium was significantly associated with biochemical failure (BF) (digital scoring, p = 0.014) and (visual scoring, p = 0.004). In the multivariate analyses, a high level of Ki-67 was an independent poor prognostic factor for biochemical failure-free survival (BFFS) (Visual scoring, Ki67, p = 0.012, HR:1.50, CI95% 1.10-2.06). In conclusion, high Ki-67 expression is an independent negative prognostic marker for biochemical failure. Our findings support the role of Ki-67 as a significant, poor prognostic factor for in prostate cancer outcome.