Nucleolin Staining May Aid in the Identification of Circulating Prostate Cancer Cells

Heather J. Chalfin, James E. Verdone, Emma E. van der Toom, Stephanie Glavaris, Michael Gorin, Kenneth Pienta

Research output: Contribution to journalArticle

Abstract

Introduction: Circulating tumor cells (CTCs) have great potential as circulating biomarkers for solid malignancies. Currently available assays for CTC detection rely on epithelial markers with somewhat limited sensitivity and specificity. We found that the staining pattern of nucleolin, a common nucleolar protein in proliferative cells, separates CTCs from white blood cells (WBCs) in men with metastatic prostate cancer. Patients and Methods: Whole peripheral blood from 3 men with metastatic prostate cancer was processed with the AccuCyte CTC system (RareCyte, Seattle, WA). Slides were immunostained with 4',6-diamidino-2-phenylindole (DAPI), anti-pan-cytokeratin, anti-CD45/CD66b/CD11b/CD14/CD34, and anti-nucleolin antibodies and detected using the CyteFinder system. DAPI nucleolin colocalization and staining pattern wavelet entropy were measured with novel image analysis software. Results: A total of 33,718 DAPI-positive cells were analyzed with the novel imaging software, of which 45 (0.13%) were known CTCs based on the established AccuCyte system criteria. Nucleolin staining pattern for segmentable CTCs demonstrated greater wavelet entropy than that of WBCs (median wavelet entropy, 6.86 × 107 and 3.03 × 106, respectively; P = 2.92 × 10-22; approximated z statistic = 9.63). Additionally, the total nucleolin staining of CTCs was greater than that of WBCs (median total pixel intensity, 1.20 × 105 and 2.55 × 104 integrated pixel units, respectively; P = 2.40 × 10-21; approximated z statistic = 9.41). Conclusion: Prostate cancer CTCs displayed unique nucleolin expression and localization compared to WBCs. This finding has the potential to serve as the basis for a sensitive and specific CTC detection method.

Original languageEnglish (US)
JournalClinical Genitourinary Cancer
DOIs
Publication statusAccepted/In press - Sep 16 2016

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Keywords

  • Circulating tumor cells
  • Disease-specific marker
  • Nucleolin
  • Prostate cancer
  • Selection-free assay

ASJC Scopus subject areas

  • Oncology
  • Urology

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