Proliferating-cell nuclear antigen (PC10) immunolabelling and other proliferation indices as prognostic factors in breast cancer.

Proliferating cell nuclear antigen, PCNA (PC10), immunolabelling was determined in 175 women with breast carcinomas and related to other established prognostic factors: flow-cytometric data, volume-corrected mitotic index, sex steroid receptor content and clinical outcome during the mean follow-up of 9 years. The maximum fraction of PCNA-positive nuclei (PCNAmax), the average fraction of positive nuclei (PCNAtot) and the number of intensely stained nuclei per microscope field (PCNAcount) were significantly related to histological grade (P < 0.001), DNA ploidy ((P < 0.001), S-phase fraction (P < 0.001), mitotic index (P < 0.001) and sex steroid receptor content (P = 0.002). PCNAmax (P = 0.015) predicted survival in univariate analysis; PCNAtot (P = 0.025), PCNAmax (P = 0.007) and PCNAcount (P = 0.019) predicted the recurrence-free survival. In axillary-lymph-node-negative tumours, PCNAtot (P = 0.092), PCNAmax (P = 0.036) and PCNAcount (P = 0.006) predicted survival and recurrence-free survival (P = 0.011), (P = 0.012) and (P = 0.006) respectively. In multivariate analysis including clinical, histological, flow-cytometric and biochemical variables, PCNAtot (P = 0.004) predicted the recurrence-free survival independently. In axillary-lymph-node-negative breast cancers, PCNAtot predicted accurately the patient survival (P = 0.002) and the recurrence-free survival (P = 0.002). The results indicate that PCNA immunolabelling has independent prognostic value particularly in local breast cancer.