The evaluation of salivary gland tumours using proliferating cell nuclear antigen.

In order to assess its discriminating and prognostic value, we studied the immunoreactivity for proliferating cell nuclear antigen (PCNA) in tissue from 52 human salivary gland tumours using the murine monoclonal antibody PC10. The PCNA percentage count, namely, the average number of positive nuclei counted per 100 randomly selected tumour cells was recorded for each tumour. Anaplastic carcinoma was used as a positive control and histologically 'normal' salivary gland and tonsil served as a negative control. A PCNA count of 30 per cent was postulated to predict malignancy within a given salivary gland tumour i.e. a PCNA count of 30 per cent or above would indicate malignant potential. This gave a sensitivity of 96.9 per cent and a specificity of 95.2 per cent and a positive predictive value of determining malignancy of 96.8 per cent. We conclude that PCNA immunoreactivity is useful in discriminating between benign and malignant salivary gland tumours and that it may have prognostic value in this diverse group of neoplasms.