The transcription factor forkhead box O1 (FOXO1) can be inactivated via its phosphorylation, resulting in suppression of apoptosis. Using immunohistochemistry, the expression of a phosphorylated form of FOXO1 was assessed in upper urinary tract urothelial carcinoma (UUTUC) specimens. Overall, phospho-FOXO1 (p-FOXO1) was immunoreactive in all 99 UUTUC specimens [12 (12.1%) weak (1+), 46 (46.5%) moderate (2+) and 41 (41.4%) strong (3+)], which was significantly (P=0.018) increased, compared with benign urothelium specimens [77/82 (93.9%): 18 (22.0%) 1+, 41 (50.0%) 2+ and 18 (22.0%) 3+]. Muscle invasion (P=0.031) and lymphovascular invasion (P=0.025) were observed more frequently in p-FOXO1(2+/3+) tumor samples compared with p-FOXO1(1+) tumor samples. No statistically significant associations between p-FOXO1 expression and tumor grade or presence of concurrent carcinoma in situ, hydronephrosis or lymph node metastasis were observed. Furthermore, the levels of p-FOXO1 and estrogen receptor-β expression were significantly (P<0.05) correlated in UUTUC samples [correlation coefficient (CC)=0.244], particularly in tumor samples from male patients (CC=0.330). Additionally, patients with p-FOXO1(3+) tumors had a significantly increased risk of cancer-specific mortality (P=0.043), compared with those with p-FOXO1(1+/2+) tumors. Multivariate analysis further demonstrated a notable, albeit not significant, association between p-FOXO1 expression and cancer-specific survival (hazard ratio=2.204; P=0.053). These findings indicate that FOXO1 is inactivated in UUTUC specimens and p-FOXO1 overexpression may serve as a predictor of poor patient outcomes.
Oncology letters. 2018 Sep 26 [Epub]
Hiroki Ide, Guiyang Jiang, Taichi Mizushima, Kazutoshi Fujita, Satoshi Inoue, Seiji Yamaguchi, Hiroaki Fushimi, Norio Nonomura, Hiroshi Miyamoto
Department of Pathology and James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA., Department of Pathology and Laboratory Medicine and James P. Wilmot Cancer Center, University of Rochester Medical Center, Rochester, NY 14642, USA., Department of Urology, Osaka University Graduate School of Medicine, Suita 565-0871, Japan., Department of Urology, Osaka General Medical Center, Osaka 558-8558, Japan., Department of Pathology, Osaka General Medical Center, Osaka 558-8558, Japan.