Introduction

Various transcription factors, including ELK1, FOXO1, NFAT, and ZKSCAN3, have been shown to contribute to bladder tumorigenesis and cancer progression. Meanwhile, we have demonstrated that androgens promote bladder cancer outgrowth via modulating the activity of some of these transcription factors. In contrast, little is known about their role in the development and growth of upper urinary tract urothelial carcinoma (UUTUC). This study aims to determine the expression status of phospho-ELK1 (pELK1) and phospho-FOXO1 (pFOXO1), their activated and inactivated forms, respectively, as well as NFATc1 and ZKSCAN3, in UUTUC and its prognostic significance.

Methods

We immunohistochemically stained for pELK1, pFOXO1, NFATc1, and ZKSCAN3 in the tissue microarrays consisting of 99 UUTUC samples and paired non-neoplastic urothelium from each case. We then evaluated the relationship between the expression of each transcription factor and clinicopathologic features available for our patient cohort.

Results

pELK1, pFOXO1, NFATc1, and ZKSCAN3 were positive in 47% [37% weak (1+), 10% moderate (2+), 0% strong (3+)], 100% (12% 1+, 46% 2+, 41% 3+), 51% (40% 1+, 9% 2+, 3% 3+), and 42% (26% 1+, 13% 2+, 3% 3+) of UUTUCs, respectively, which were significantly higher (pELK1: 25%, P=0.002; pFOXO1: 94%, P=0.018; NFATc1: 24%, P=0.038) or lower (ZKSCAN3: 86%, P<0.001) than in benign urothelial tissues. Five (33%) of 15 low-grade versus 42 (50%) of 84 high-grade UUTUCs (P=0.036) and 13 (35%) of 37 non-muscle-invasive (NMI) versus 34 (55%) of 62 muscle-invasive (MI) UUTUCs (P=0.065) were immunoreactive for pELK1. Similarly, 29 (78%) NMI versus 58 (94%) MI UUTUCs (P=0.031) were moderately or strongly positive for pFOXO1. However, there were no statistically significant associations between pELK1/pFOXO1/NFATc1/ZKSCAN3 expression and pN/M status. Kaplan-Meier and log-rank tests revealed that patients with high (2+) pELK1 tumor (P=0.008), high (3+) pFOXO1 tumor (P=0.059), high (2+/3+) NFATc1 tumor (P=0.005), or high (3+) ZKSCAN3 MI tumor (P=0.069) had higher risks of cancer-specific mortality.

Conclusions

Compared with non-neoplastic urothelium, significant increases and a decrease in the expression of pELK1/pFOXO1/NFATc1 and ZKSCAN3, respectively, in UUTUC were seen. The current results also support our preclinical findings indicating correlations of ELK1/FOXO1 activation with urothelial tumor progression/regression, respectively. Furthermore, pELK1/NFATc1 overexpression was found to serve as predictors of poor prognosis.

Funding

None