Apoptotic protein expression in favorable-histology Wilms tumor correlates with tumor recurrence

Abstract

Outcome for patients with Wilms tumor (WT) with favorable histology is good. Deletions of chromosomes 1p and 16q impart a poorer outcome. Value of apoptotic protein expression is not clear. Expression of four immunohistochemically detectable apoptosis-regulating proteins (bcl-2, bcl-x, bax and p53) were analyzed in 30 specimens of WT and compared to recurrence and recurrence-free survival (RFS). The 30 patients included ranged from 4 to 72months in age (mean 31). The mean available follow-up was 35.3months (range 1-54). Six patients developed recurrence. The 5-year RFS for blastema-predominant tumors was 40% as compared to 91% for triphasic histology which was significant (p=0.048). The 5-year RFS in patients with bcl-2 negative tumors was 63% as compared to 100% for bcl-2 positive tumors, the difference being significant (p=0.019). The 5-year RFS in patients with p-53 positive tumors was 27% as compared to 91% for p-53 negative tumors; however, this difference in the RFS was not statistically significant (p=0.143). bax and bcl-x expression were not related to the RFS. Tumors that are bcl-2 negative have a relatively higher recurrence rate and a poorer RFS. They may benefit from a more intensive follow-up regime for early detection of recurrence.