Standardized AgNOR analysis in actinic keratosis

To assess if the quantity of silver-stained nucleolar organizer region (A.- NOR) proteins predicts the behavior of actinic keratosis (AK), we performed a standardized A-NOR analysis on 51 cases of AK; in addition, 10 cases of squamous cell (SCC) and 10 cases of basal cell (BCC) carcinomas and 10 norm al skin samples were also studied. A-NOR analysis was performed on formalin -fixed and paraffin-embedded sections according to the guidelines of the Co mmittee on AaNOR Quantification (1995), evaluating the mean area ( mum(2)) of AgNORs per nucleus (NORA). A highly significant P value (< 0.001) was fo und in the comparison among NORA values of normal skin (1.869 <mu>m(2); SD +0.332), AK (3.988 mum(2); SD +0.914), BCC (3.044 mum(2); SD +0.254), and S CC (5.286 mum(2); SD +0.920). In AK, a progressive increase of mean NORA va lues was observed moving from Stage I (3.161 mum(2); SD +0.600) to Stage II (3.455 mum(2); SD +0.562), Stage III (4.360 mum(2), SD +0.295), and Stage IV (5.168 mum(2); SD +0.694); highly significant differences (P < 0.001) we re noted when Stages I or II were compared with Stage III or Stage IV or be tween these latter stages. The AgNOR quantity may identify AKs with high pr oliferative activity and increased tendency to develop into invasive SCC.