Fragile histidine triad protein, WW domain-containing oxidoreductase protein Wwox, and activator protein 2γ expression levels correlate with basal phenotype in breast cancer

Authors

  • Gulnur Guler MD,

    1. Department of Pathology, Hacettepe University, Ankara, Turkey
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    • The first 2 authors contributed equally to this article.

  • Kay Huebner PhD,

    Corresponding author
    1. Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University Medical Center, Columbus, Ohio
    • Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Comprehensive Cancer Center, Biomedical Research Tower, Room 916, 460 W. 12th Avenue, Columbus, OH 43210
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    • The first 2 authors contributed equally to this article.

    • Fax: (614) 688-8675

  • Cigdem Himmetoglu MD,

    1. Department of Pathology, Hacettepe University, Ankara, Turkey
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  • Rafael E. Jimenez MD,

    1. Department of Pathology, Ohio State University Medical Center, Columbus, Ohio
    Current affiliation:
    1. Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota
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  • Stefan Costinean MD,

    1. Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University Medical Center, Columbus, Ohio
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  • Stefano Volinia PhD,

    1. Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University Medical Center, Columbus, Ohio
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  • Robert T. Pilarski MS,

    1. Division of Clinical Genetics, Ohio State University Medical Center, Columbus, Ohio
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  • Mutlu Hayran MD,

    1. Institute of Oncology and Preventive Oncology, Hacettepe University, Ankara, Turkey
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  • Charles L. Shapiro MD

    1. Division of Hematology and Oncology, Department of Internal Medicine, Ohio State University Medical Center, Columbus, Ohio
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Abstract

BACKGROUND:

The expression of fragile histidine triad protein (Fhit) and WW domain-containing oxidoreductase protein (Wwox), tumor suppressors that are encoded by fragile (FRA) loci FRA3B and FRA16D, are lost concordantly in breast cancers. In the current study, the authors examined correlations among Fhit, Wwox, the activator protein 2 transcription factors AP2α and AP2γ, cytokeratins 5 and 6 (CK5/6), epidermal growth factor receptor (EGFR), estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) and their associations with breast cancer phenotypes.

METHODS:

Tissue microarrays constructed from 837 breast cancer blocks were immunostained. Expression in >10% of tumor cells was considered positive for cytoplasmic CK5/6, membranous EGFR, and nuclear AP2α and AP2γ. Cytoplasmic Fhit and Wwox staining was scored according to staining intensity. ER, PR, and HER-2 status of tumors was derived from records. Correlations among immunohistochemical markers and tumor subtypes were assessed by univariate and multivariate statistical methods.

RESULTS:

Triple-negative tumors had more frequent expression of EGFR, CK5/6 (P < .001), and AP2γ (P = .003) and more frequent loss of Fhit and Wwox (P < .001), and an inverse correlation was observed between Fhit, Wwox expression and EGFR, ER, and PR expression (P < .001). Reduced Fhit expression was more common in HER-2-positive and AP2γ-positive cases (P < .001 and P = .002, respectively). There was a direct correlation noted between Fhit and Wwox (P < .001) and a borderline positive relation between AP2α and AP2γ (P = .054).

CONCLUSIONS:

The results from this investigation suggested that reduced expression levels of Fhit, Wwox, and nuclear AP2γ have roles in the pathogenesis of basal-like differentiation in breast cancer. Alteration in the expression of fragile site genes occurs in most of these cancers and may contribute to defects in DNA repair, as observed in breast cancer 1 (BRCA1)-deficient cancers. Thus, DNA damage response checkpoint proteins may be targets for treatment. Cancer 2009. © 2009 American Cancer Society.

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