title: DNA content in malignant salivary gland tumours.
abstract: OBJECTIVE
  Our aim was to evaluate the DNA content in malignant salivary gland tumours using image cytometry and its possible relationships with clinical and morphologic findings, disease course and prognosis.
  
  
  METHODS
  The study sample comprised 31 patients diagnosed and treated for primary malignant salivary gland tumours. Formalin-fixed, paraffin-embedded surgical specimens of all patients were Feulgen-stained for DNA content analysis by image cytometry. Statistical analysis was used to investigate possible relationships between DNA content variables and clinical and histological findings, disease course and patient survival.
  
  
  RESULTS
  Seventeen (55%) cases of our sample were graded as DNA diploid, four (13%) as DNA aneuploid and 10 (32%) as DNA multiploid. In 15 (48%) cases, the 5c exceeding rate (5cER) was higher than 1.7%. DNA ploidy correlated with N stage and tumour size. DNA ploidy and 5cER had a statistically significant prognostic influence on overall and disease-free survival in univariate analysis. However, in multivariate analysis, stage classification was the only parameter with an independent prognosis value.
  
  
  CONCLUSIONS
  Abnormal DNA content is a common finding in salivary gland cancers. Our results suggest an important role of DNA content analysis in the evaluation of these tumours.
authors.affiliation: Oral Surgery and Oral Medicine Department, Higher Institute of Health Sciences (ISCSN), Porto, Portugal. lmonteiro_md@hotmail.com
authors.forename: L S
authors.initials: LS
authors.lastname: Monteiro
authors.forename: C
authors.initials: C
authors.lastname: Palmeira
authors.forename: M J
authors.initials: MJ
authors.lastname: Bento
authors.forename: C
authors.initials: C
authors.lastname: Lopes