The prognostic significance of proliferating cell nuclear antigen in patients with lymph node-positive breast cancer

Objective: To evaluate the prognostic significance of proliferating cell nuclear antigen (PCNA) in patients with lymph node-positive primary breast cancer. Design: A retrospective study. Setting: A tertiary care hospital. Study Participants: A consecutive series of 123 patients with lymph node- positive primary breast cancer. Intervention: The PCNA-labeling index [(PCNA- positive cells/1000 cells) x 100] was quantified in paraffin-embedded tissue specimens from 123 patients with lymph node-positive primary breast cancer by immunohistochemical staining. Other important clinicopathological variables, including estrogen receptor status, histological grade, lymph node status, primary tumor status, ploidy pattern, S-phase fraction, and TNM staging, were also identified and evaluated. Main Outcome Measures: The influence of the PCNA- labeling index on the disease-free survival rate and overall survival rate. Results: The PCNA-labeling index of the tissue specimens tested from 123 patients ranged from 11% to 82%. The PCNA-labeling index was closely related to primary tumor stains, histological grade, TNM staging, and S- phase fraction. Between patients with a high PCNA-labeling index (>35%) and those with a low PCNA labeling index (≤35%), there were significant (P<.01) differences in both 5-year disease-free survival rates (2% vs 85%) and 5- year overall survival rates (2% vs 92%). When the PCNA-labeling index and all the clinicopathologic variables were entered into a multivariate analysis for either disease-free survival or overall survival by the Cox proportional hazards model, the PCNA-labeling index emerged as an independent prognostic factor. Conclusion: Based on our results, the PCNA-labeling index potentially is a useful prognostic factor for lymph node-positive primary breast cancer.