In prostate cancer needle biopsies, detections of PTEN loss by fluorescence in situ hybridization (FISH) and by immunohistochemistry (IHC) are concordant and show consistent association with upgrading

C. G. Picanço-Albuquerque, C. L. Morais, F. L.F. Carvalho, S. B. Peskoe, J. L. Hicks, O. Ludkovski, T. Vidotto, H. Fedor, E. Humphreys, M. Han, E. A. Platz, A. M. De Marzo, D. M. Berman, T. L. Lotan, J. A. Squire

Research output: Contribution to journalArticlepeer-review

Abstract

The prognostic value of phosphatase and tensin homolog (PTEN) loss in prostate cancer has primarily been evaluated by either fluorescence in situ hybridization (FISH) or immunohistochemistry (IHC). Previously, we found that PTEN loss by IHC was associated with increased risk of upgrading from biopsy (Gleason 3 + 3) to prostatectomy (Gleason 7+). Now, using an evaluable subset of 111 patients with adjacent biopsy sections, we analyzed the association between PTEN deletion in cancer and the odds of upgrading by a highly sensitive and specific four-color FISH assay. We also compared the concordance of PTEN loss by IHC and PTEN deletion by FISH. PTEN deletion was found in 27 % (12/45) of upgraded cases compared with 11 % (7/66) of controls (P = 0.03). Cancers with PTEN deletions were more likely to be upgraded than those without deletions (adjusting for age odds ratio = 3.40, 95 % confidence interval 1.14–10.11). With respect to concordance, of 93 biopsies with PTEN protein detected by IHC, 89 (96 %) had no PTEN deletion by FISH, and of 18 biopsies without PTEN protein by IHC, 15 had homozygous or hemizygous PTEN deletion by FISH. Only 4 biopsies of the 93 (4 %) with PTEN protein intact had PTEN deletion by FISH. When the regions of uncertainty in these biopsies were systematically studied by FISH, intra-tumoral variation of PTEN deletion was found, which could account for variation in immunoreactivity. Thus, FISH provides a different approach to determining PTEN loss when IHC is uncertain. Both FISH and IHC are concordant, showing consistent positive associations between PTEN loss and upgrading.

Original languageEnglish (US)
Pages (from-to)607-617
Number of pages11
JournalVirchows Archiv
Volume468
Issue number5
DOIs
StatePublished - May 1 2016

Keywords

  • Gleason upgrade
  • Hemizygous and homozygous genomic deletion
  • Prognostic biomarker assay
  • Tumor suppressor gene

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Molecular Biology
  • Cell Biology

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