HMGB1 expression in urothelial carcinoma of the bladder

Purpose: HMGB1, the most important member of the high mobility group box protein family, is a nuclear protein with different functions in the cell; it has a role in cancer progression, angiogenesis, invasion, and metastasis development. We studied the expression of HMGB1 and whether it is a prognostic factor in urothelial carcinoma of bladder (UCB) or not. Methods: The study included 90 cases that were histopathologically diagnosed with UCB in the tissue samples obtained by transurethral resection (TUR). HMGB1 expression was investigated by immunohistochemistry. Results:A total of 90 patients, 80 (88.9%) male and 10 (11.1%) female, were enrolled in the study. The histopathological diagnosis was infiltrating urothelial carcinoma (IUC) in 63 (70.0%) and non-invasive papillary urothelial carcinoma (NIPUC) in 27 (30.0%). When the NIPUC cases were grouped according to grade, 24 (88.9%) of the cases were low grade and 3 (11.1%) were high grade. HMGB1 expression was found positive in 51 (56.796) and negative in 39 (43.3%) of the patients. HMGB1 expression was significantly higher in IUCs (p=0.046). Conclusion: The results of our study demonstrate that HMGB1 overexpression has a significant role in UCB progression and it corroborates the idea that it might be an important prognostic factor.