The tumor stage and grade are the most recognized prognostic factors in UTUC [1, 2, 19,20,21,22]. However, herein, no significant association was identified with patients RFS. In the study of Olgac et al. , the stage was the most potent predictor of patient survival similar to the urothelial tumors of lower urinary tract. In a multi-institutional dataset of patients investigated by Novara et al. , the stage as well as the lymph nodes and the presence of synchronous muscle-invasive bladder cancer were independent predicting factors of cancer-specific survival. In addition, Langner et al.  found that stage was the only independent prognostic factor regarding disease-free survival. Two years later, in multivariate analysis of 190 consecutive invasive UTUC, these researchers considered that pT classification and vascular invasion were independent prognostic factors of metastasis-free survival .
In the present study, the positive surgical margin was associated significantly with shorter RFS, supporting its putative prognostic role in UTUC. Interestingly, Formont et al.  reported tumor recurrence and poor prognosis in all patients with positive surgical margins. Using univariate analysis, Olgac et al.  showed that margin status was significantly associated with patient survival. These results altogether highlight the importance of high quality of the initial tumor resection and checking margin status.
The prognostic significance of the cell cycle regulator, p53, in UTUC has been investigated previously with conflicting results [3,4,5, 8, 23]. In an early study, Terrell et al.  neglected any prognostic significance of p53 since there were no significant association with grade, stage, and cancer-specific survival. Ten years later, Fromont et al.  ignored as well the association between p53 and patient survival. Nonetheless, herein, only p53 expression was associated significantly with shorter RFS as well as with stage, positive surgical margin, and Ki-67 expression. Interestingly, previous studies reported significant correlations between p53 expression and advanced stage, high grade, and female gender as well as with disease-free, cancer-specific, and overall survival rates [3, 5]. Furthermore, p53 may be a useful marker to predict recurrence patterns and could be a prognosis predictor of UTUC in addition to tumor grade and growth pattern .
Currently, positive p27 expression was associated significantly with tumor stage and grade. However, we did not find any significant association with RFS. Similarly, in the early study of Nakanishi et al. , although p27 expression decreased significantly with stage and grade, no correlation was reported with overall and disease-free survival rates. Using tissue microarray technology, Fromont et al.  and Munari et al.  found also no significant prognostic interest of p27 expression in UTUC. However, more recently, although no association was described between p27 expression and tumor stage or grade, loss of p27 expression was correlated with tumor architecture and patient overall survival . In fact, as described in papillary bladder carcinomas, Sarsik et al.  found loss of p27 expression in 33.3% of UTUC samples with invasive pattern while all noninvasive cases exhibited p27 expression. Similar to p27 expression loss, tumors with lower p27 expression displayed invasive growth pattern .
Ki-67 expression has been reported previously in 53 to 88% of UTUC [8, 10, 11, 26, 27]. In our study, we observed positive Ki-67 expression in 69.7% of cases. The significant association between the positive Ki-67 expression and the tumor stage, grade, and vascular invasion suggest the involvement of Ki-67 in UTUC invasiveness. Previously, a higher Ki-67 expression was found as well in T2-T4 tumor compared with Tis-T1 tumors and was associated with poor survival and high risk of disease progression . Furthermore, a significant association was identified between Ki-67 overexpression and adverse clinicopathological features and poor prognosis in patients after radical nephroureterectomy , supporting its value as a promising indicator predicting survival . In retrospective and prospective analyses, Krabbe et al.  considered that Ki-67 is an independent predictor of RFS in patients with high-grade UTUC. Nonetheless, herein, we found no significant association of Ki-67 expression with RFS.
Unlike previous reports, no significant prognostic value for E-cadherin expression was identified herein [8, 13, 14, 28]. In the Nakanishi et al.  study, E-cadherin expression was associated with stage and grade, pattern of growth, disease-free, and overall survival rates only in univariate analysis. Using tissue microarray technology, loss of E-cadherin expression was the only significant independent prognostic factor that was able to predict recurrence in patients with low-grade non-invasive UTUC, requiring hence an accurate follow-up . Interestingly, in Velickovic et al. study , the loss of E-cadherin expression was correlated with the advanced stage of sporadic urothelial carcinomas as well as in patients with endemic nephropathy. However, Reis et al.  contradicted all previous studies and considered that the overexpression of E-cadherin is related to tumor recurrence and disease-free survival rates.
There were only a few studies of HER2 expression in UTUC [15, 16, 29, 30]. In the present study, we did not detect any HER2 positivity in all investigated cases as described in the early study of Bjerkehagen et al. , while only a low rate of HER2 overexpression and HER2 amplification was reported by Langner et al. , suggesting that HER2-targeted therapy would be beneficial for only a small number of patients. Likewise, as HER2 amplification and overexpression were rare events and more common in patients with high-grade tumors, lymph node invasion, and an inverted growth pattern, Vershasselt-Crinquette et al.  and Ehsani et al.  considered that only those patients may be potential candidates for Trastuzumab therapy.