Frequency and Prognostic Value of PTEN Loss in Patients with Upper Tract Urothelial Carcinoma Treated with Radical Nephroureterectomy

Purpose: To our knowledge the frequency and prognostic significance of PTEN protein expression in upper tract urothelial carcinoma have not yet been investigated in large studies. We analyzed PTEN protein status and its association with disease recurrence and survival outcomes in a large, multi-institutional upper tract urothelial carcinoma cohort. Materials and Methods: We retrospectively analyzed the records of 611 patients with upper tract urothelial carcinoma treated with radical nephroureterectomy between 1991 and 2008 at a total of 7 institutions. Median followup was 23 months. Tissue microarrays and immunohistochemical PTEN staining (monoclonal antibody) were performed. Univariable and multivariable Cox regression models were created to address the association of PTEN protein expression with disease recurrence, and cancer specific and overall mortality. Results: PTEN staining was absent in 45 cases (7.4%). Patients with PTEN loss had significantly advanced pathological tumor stage and grade (p < 0.001), and higher rates of lymph node metastasis (p < 0.01) and lymphovascular invasion (p < 0.001) compared to patients with PTEN expression. PTENloss was associated with disease recurrence, and cancer specific and overall mortality on univariable Cox regression analyses. However, on multivariable Cox regression analyses adjusted for the effect of standard clinicopathological features PTEN loss was only associated with overall mortality (HR 1.69, 95% CI 1.09-2.61, p = 0.02). Conclusions: In patients undergoing radical nephroureterectomy for upper tract urothelial carcinoma loss of PTEN protein expression is rare but associated with features of biologically aggressive disease such as higher grade and stage as well as lymph node metastasis. Loss of PTEN expression was associated with overall mortality. PTEN loss seemed to promote worse outcomes in this relatively small group of patients.