While the majority of neoplastic epithelial cells of WHO type B1 thymomas displayed weak-to-moderate nuclear (95% of all nuclei stained positive for HMGB1) and strong cytoplasmic (33% of cells showed cytoplasmic staining) staining there were conspicuous epithelial cells in all B1 thymomas examined that showed clearly no nuclear staining for HMGB1 (figure 2). The gene discussed is HMGB1; the disease is thymoma.