https://www.selleckchem.com/products/inv-202.html 001) and the presence of necrosis (p = 0.021). In univariate survival analysis, we identified the following three novel morphological features associated with survival exophytic polypoid growth pattern, tumor density, and single mesothelium layered tubular structures. After adjustments, low nuclear grade (p less then 0.001) and presence of exophytic polypoid growth (p = 0.024) were associated with prolonged survival. These results may aid in estimating DMM prognosis. Flat urothelial lesions with atypia may pose significant diagnostic challenges. Given frequent increased proliferation rates in florid reactive urothelial atypia and limited studies on the interpretation of p53 stains in urothelium (following current standard guidelines for correlation with P53 mutation status), we sought to further study the discriminatory value of Ki-67 and p53 for florid reactive urothelial atypia versus urothelial carcinoma in situ (CIS). Bladder specimens diagnosed as reactive urothelial atypia (n=40) and CIS (n=40) were assessed by immunohistochemical staining with antibodies for Ki-67, p53, CD44, and CK20. Immunoreactivity was scored based on percent cells positive for Ki-67 and pattern of reactivity with p53 [aberrant diffuse strong positive or negative; normal patchy/wild type]. CD44 and CK20 reactivity patterns served as adjunctive internal validation controls for reactive urothelial atypia and CIS, as previously described. In reactive urothelial atypia, Ki-67 ranged from 0% to 90% 40%) showed focal expression in the non-neoplastic basal cell layer; 24 cases (60%) demonstrated no staining. In summary, Ki-67 has poor discriminatory value for reactive urothelial atypia versus CIS, and adds little to the classic CK20/CD44 immunophenotype. While p53 sensitivity for CIS is relatively low (30%) and interpretation as either wild type or negative may be challenging in a small subset of cases, strong and diffuse nuclear reactivity was 1