HMGB1 and thymoma: The observed progressive loss of HMGB1 in the nucleus of cancer cells from WHO type B thymomas and thymic carcinoma and conversely the increase of cytoplasmic staining intensity, starting with no expression of HMGB1 in the cytoplasm of epithelial tumor cells of WHO type A and AB thymomas, strong expression in B1 thymomas, moderate expression in type B2, and weak expression in type B3 and some thymic carcinomas; let us hypothesize that there could be a misbalance in the regulation of autophagy and apoptosis towards autophagy of malignant epithelial tumor cells.