PCNA IMMUNOSTAINING IN BREAST-CANCER

Expression of proliferating cell nuclear antigen (PCNA) has been shown to be of prognostic value in patients with certain types of cancer. T he aim of this study was to determine if the abundance of PCNA is inve rsely correlated with survival of patients with breast cancer. Paraffi n blocks were available from 68 patients, all of whom had been followe d clinically for at least 5 years. Sections from 20 patients showed no reactivity to PCNA and were excluded from the study because it was no t possible to distinguish between true negatives and false negatives ( those due to poor fixation of the original specimens). The PCNA index (the number of stained cancer cells as a percentage of the total numbe r of cancer cells present) was calculated for the remaining 48 patient s. Results were analysed by Wilcoxon's rank sum test (two tailed) and Pearson's correlation coefficient. There was no statistical difference between the PCNA indices of those patients dead from their disease wi thin 5 years of diagnosis compared with those alive and without signs of breast cancer at 5 years. There was also no correlation between PCN A index and size of the cancer, involvement of axillary lymph nodes, t ime to recurrence or time to death. There was, however, a significant correlation between PCNA index and histological grade (P = 0.029). It appears that PCNA staining of stored paraffin sections is of little pr ognostic value in patients with breast cancer.