title: Slide-based cytometry for predicting malignancy in solid salivary gland tumors by fine needle aspirate biopsies.
abstract: BACKGROUND
  To minimize hospitalization and morbidity for a patient with a solid tumor of a salivary gland, malignancy must be confirmed or excluded as soon as possible. This information cannot be obtained preoperatively by existing standard procedures. Minimal-invasive approaches with adequate diagnostic analysis represent a promising precondition for optimized therapy.
  
  
  METHODS
  For fine needle aspirate biopsies (FNABs), laser scanning cytometry (LSC) offers a semi-automated slide-based technology for objective and quantitative analysis. We have established an assay for FNABs from salivary gland tumors. FNAB cells were stained for cytokeratin and DNA followed by LSC analysis. The cells were subsequently HE-stained and were relocalized on the slide. The LSC analysis quantitatively determines the DNA index (DI) of the tumor cells taking leukocytes as internal DNA diploid standard. Histograms with 0.95 < DI < 1.05 and 1.9 <DI <2.1 were defined as DNA euploid, whereas any other DI was defined as DNA aneuploid. The percentage of cytokeratin positive cells with DI > 2.5 (i.e., 5c exceeding rate, 5cER) was calculated. Samples with DNA aneuploid peaks or with 5cER > 5% were classified as malignant. Routine histopathology was performed as a control.
  
  
  RESULTS
  FNABs from 51 solid salivary gland tumors (41 parotid gland, six submandibular, four parapharyngeal) were analyzed with this assay. Eleven of 14 malignant tumors were DNA aneuploid by LSC analysis. All benign tumors showed diploid DNA content. The positive predictive value for malignancy was 1.0, the negative predictive value was 0.93, the correlation with routine histopathology was highly significant (p = 7.6 x 10(-9), Fisher's exact test). The calculated specificity of LSC analysis was 1.0 and the sensitivity was 0.79.
  
  
  CONCLUSIONS
  This pilot study demonstrates the validity of slide-based cytometry for the preoperative prediction of malignancy in solid tumors being inaccessible for incision biopsy but suitable for FNABs such as those of the parotid gland.
authors.affiliation: Department of Otorhinolaryngology/Plastic Surgery, University of Bonn, Bonn, Germany. gerstaoh@web.de
authors.forename: Andreas O H
authors.initials: AO
authors.lastname: Gerstner
authors.forename: Anne-Kathrin
authors.initials: AK
authors.lastname: Müller
authors.forename: Julia
authors.initials: J
authors.lastname: Machlitt
authors.forename: Attila
authors.initials: A
authors.lastname: Tárnok
authors.forename: Andrea
authors.initials: A
authors.lastname: Tannapfel
authors.forename: Anette
authors.initials: A
authors.lastname: Weber
authors.forename: Friedrich
authors.initials: F
authors.lastname: Bootz
mesh_terms: D008949:Adenoma, Pleomorphic / Q000235:genetics / Q000473:pathology*; D000782:Aneuploidy; D001707:Biopsy, Needle; D004273:DNA, Neoplasm / Q000032:analysis; D006801:Humans; D018613:Microscopy, Confocal; D010307:Parotid Neoplasms / Q000235:genetics / Q000473:pathology*; D010865:Pilot Projects; D011003:Ploidies; D011237:Predictive Value of Tests; D011379:Prognosis; D013365:Submandibular Gland Neoplasms / Q000235:genetics / Q000473:pathology
chemical_list: D004273:DNA, Neoplasm