Does Immunohistochemical Staining of P53, Ki 67 and Cyclin A Accurately Predict Wilms Tumor Recurrence and Survival?

Objective: To evaluate whether p53, cyclin A and ki67 immunohistochemical (IHC) assay can be used as predictors for Wilms' tumor (WT) unfavorable outcomes.

Methods: It is a non-concurrent cohort study including patients who underwent nephrectomy for WT from January 2000 to December 2015 in a tertiary referral center. Over a 5- year follow-up, unfavorable events, including relapse and cancer-specific mortality (CSM), were recorded. P53, cyclin A, and ki67 IHC assay were carried out for formalin-fixed paraffin-embedded WT samples.

Results: After excluding those who did not meet the inclusion criteria, 75 patients were enrolled. Of the patients, 15/75 (20%) experienced WT relapse while 11/75 (14.6%) died of WT over five years. Unfavorable histology (UFH), including prominent blastemal components and anaplasia, was found in 15/75 (20%) children.Cyclin A immunopositivity was associated with high rates of relapse and CSM. P53 and ki67 positive IHC assay did not show any statistically significant association with unfavorable outcomes. Other risk factors e.g. advanced staging, UFH, extracapsular extension, tumor rupture, lymphadenopathy, and venous thrombosis were not associated with poor prognosis. However, the presence of residual tumors was accompanied by lower survival rates.

Conclusion: Cyclin A IHC assay can be used as a predictor of WT recurrence and CSM. Further studies with prospective patterns and a larger sample size are needed. WT: Wilms' tumor, UFH: unfavorable histology, IHC: immunohistochemical, PI: proliferation index, RFS: relapse-free survival, CSS: cancer-specific survival, FH: favorable histology, CSM: cancer-specific mortality, CDK: cyclin-dependent kinase.