Rrapaj E, et al. - Researchers performed an expression analysis of High-mobility group box-1 (HMGB1) in histologic samples of malignant pleural mesothelioma (MPM). Findings suggested the utility of HMGB1 as a prognostic biomarker in MPM when detected by immunohistochemistry. However, HMGB1 cannot be considered a diagnostic biomarker in histologic samples of mesothelioma because of its expression in normal and reactive mesothelial cells.