p53 overexpression in the multistep process of esophageal carcinogenesis.

The timing of p53 mutation in the multistep process of esophageal carcinogenesis is still under debate. We tested p53 expression in 16 samples of low-grade and 29 samples of high-grade esophageal dysplasia (ED) coexisting with esophageal squamous cancer (ESC) in 31 patients who underwent total esophagectomy. In normal mucosa, a positive immunoreaction was detected in 10 of 31 cases, always restricted to the lower half of the epithelial thickness. We detected p53-positive nuclei in 11 of 16, 23 of 29, and 23 of 31 samples of low-grade ED, high-grade ED, and ESC, respectively. Cases exhibiting positive staining in dysplastic samples also demonstrated positive immunoreaction in the carcinomatous tissue. Immunoreactivity in cancer cells was never found in the absence of positive dysplastic nuclei. A significantly higher score of immunoreactive nuclei was detected in high-grade versus low-grade and in low-grade compared with normal mucosa. These data suggest that p53 mutation may represent an early event in esophageal oncogenesis.

Proliferating cell nuclear antigen (PCNA) and recurrence in patients with cutaneous melanoma.

A positive correlation between PCNA and the most important histoprognostic factors of cutaneous melanoma has been demonstrated. The aim of our work was to evaluate the efficacy of PCNA in predicting melanoma recurrence and to compare it with that of Breslow thickness. One-hundred and fifteen patients (75 women, 40 men; mean age 50 years) with primary cutaneous melanoma were retrieved. pTNM stages were as follows: stage I, 54 patients; stage II, 31 patients; stage III, 26 patients; and stage IV, four patients. The mean follow-up period was 55 months (range 2-260). Six patients developed lymph node metastases and 28 developed distant metastases; 27 patients died within 2-202 months from diagnosis. Tumour thickness was re-evaluated for each case. PCNA immunostaining was performed using the avidin-biotin complex method and the percentage of PCNA-positive tumour cells was indicated as the PCNA index. In order to evaluate and compare the PCNA index and Breslow thickness as predictors of recurrence, the receiver-operating characteristic (ROC) curve method, based on true-positive and false-positive rates was used. The PCNA index showed the highest true-positive rates and the lowest false-positive rates in the 5-30 interval. The PCNA index optimal cut-off is 20, characterized by 70% sensitivity and 80% specificity; Breslow thickness optimal cut-off is 3.5 mm, with 40% sensitivity and 90% specificity. Our results indicate that the PCNA index has a higher efficacy in predicting locoregional and distant recurrences in patients presenting primary cutaneous melanoma.