Proliferative activity in oral salivary gland tumors: the role of PCNA and AgNOR assessed by a double staining technique

The aim of this study was to evaluate the role of PCNA and AgNOR in the assessment of salivary gland tumor proliferation using a double staining technique. Ten cases of pleomorphic adenoma (PA) and seventeen cases of adenoid cystic carcinoma (ACC) were examined. Numeric and morphometric parameters of AgNOR were evaluated and compared in PCNA-positive and PCNA-negative nuclei. There were statistically significant differences in AgNOR numbers, perimeters and contour indices between PCNA-positive and -negative nuclei in the PA samples. The ACC samples demonstrated significant differences only in the AgNOR areas. Our results show that in salivary gland tumors there is not always a relationship between proliferative activity evaluated by AgNOR numeric and morphometric parameters and PCNA immunostaining.