XIAP as a prognostic marker of early recurrence of nonmuscular invasive bladder cancer.

BACKGROUND

Dysregulation of apoptosis has been implicated not only in carcinogenesis and tumor progression but also in tumor recurrence. We investigated whether the expression of X-linked inhibitor of apoptosis (XIAP) might predict early recurrence in patients with non-muscular invasive bladder cancer.

METHODS

The cohort comprised 176 consecutive patients with primary superficial bladder cancer treated with transurethral resection. Immunohistochemical staining using the standard avidin-biotin-peroxidase technique and RT-PCR were used to detect XIAP protein and mRNA expressions in cancer tissues. The relationship between XIAP expression and clinicopathological characteristics, cancer recurrence were analyzed.

RESULTS

XlAP expression was observed in 108 cases (61.4%) and no expression in 68. There was no correlation between XIAP expression rate and the tumor pathological grade, but was an apparent trend toward the increased XIAP levels from well (G1) to poor (G3) differentiated cancer. Eighty-two (46.6%) patients experienced tumor recurrence at a mean of 28.6 months of the follow-up; 66 of them expressed XIAP (61.1%) and 16 were XIAP negative (23.5%). Twelve patients presented with invasive disease at the time of relapse and all of them expressed XIAP. Patients without XIAP expression or with low tumor grades had significantly higher recurrence-free survival than those with XIAP expression (log rank test P = 0.0015) or high tumor grades (log rank test P < 0.001). Multivariate analysis revealed that XIAP expression, tumor grade, and tumor number were independent predictors for the recurrence of non-muscular invasive bladder cancer (P = 0.004, 0.016, and 0.043, respectively).

CONCLUSIONS

XIAP may be considered as a new independent prognostic marker for early recurrence of non-muscular invasive bladder cancer.