DNA ploidy analysis in salivary gland tumours by image cytometry

Authors

  • P. A. Vargas,

    1. Department of Oral Diagnosis, Oral Pathology Section, Dental School of Piracicaba, University of Campinas (UNICAMP), Piracicaba-SP, Brazil
    2. Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
    Search for more papers by this author
  • A. Torres-Rendon,

    1. Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
    Search for more papers by this author
  • P. M. Speight

    1. Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, Sheffield, UK
    Search for more papers by this author

  • None of the authors have a commercial or other association that might pose a conflict of interest with a subject of the manuscript.

Prof. Paul Michael Speight, Head of the Department of Oral Pathology, School of Clinical Dentistry, The University of Sheffield, Claremont Crescent, Sheffield, S10 2TA, England, UK. Tel: 44(0) 114 271 7951, Fax: 44(0) 114 271 7894, E-mail: p.speight@sheffield.ac.uk

Abstract

Aim:  To determine whether DNA ploidy by image cytometry is a good diagnostic tool to distinguish benign and malignant salivary gland tumours.

Methods:  A total of 62 salivary gland tumours were studied. Cases were histologically diagnosed [haematoxylin and eosin (H&E)]. According to the World Health Organization (WHO) classification, there were 14 mucoepidermoid carcinomas (MEC), 11 adenoid cystic carcinomas (ACC), 10 pleomorphic adenomas (PA), 10 carcinoma ex PA (CEPA), 9 acinic cell carcinomas (ACCa), 3 polymorphous low-grade adenocarcinomas (PLGA), 2 papillary cystadenocarcinomas (PC), 1 myoepithelial carcinoma (MC), 1 undifferentiated carcinoma (UC) and 1 mucinous adenocarcinoma (MA). Paraffin sections (40 μm) were micro-dissected to isolate tumour areas; cell nuclei were extracted and Feulgen-stained cytospin monolayers were analysed using a DNA image cytometry system. For each case, DNA index (DI) was calculated relative to internal controls (lymphocytes; DI = 1.0). Cases were categorized as diploid or aneuploid and the proportion of cells over 5c was also calculated.

Results:  Fifty-three of 62 salivary gland tumours were uniformly diploid. Only nine cases were aneuploid: five CEPA, one low-grade MEC, one PC, one UC and one MA.

Conclusions:  The vast majority of salivary gland tumours were diploid. High-grade malignancies may be aneuploid, and ploidy may be useful to identify malignant change in atypical PA. Further, larger studies are needed to confirm our results and to further evaluate the usefulness of the technique in high-grade lesions.

Ancillary