Fig. 6.

Expression of HMGB1 in BCs using human tissue microarray. (A) Immunohistochemistry of HMGB1 expression in human normal breast tissue (top) and BC (bottom). Specimens were incubated with anti-HMGB1 antibody (1:100) overnight at 4 °C, followed by the treatment with streptoavidin-biotin complex (1:100) for 60 min, and visualized with the use of a DAB substrate-chromogen solution. HMGB1-positive cells are stained in brown. Scale bar 50 µm. (B) Number of HMGB1-positive cells in human normal breast tissue (n = 6) and BC (n = 51). HMGB1⁺ cells on specimens were counted using a BZ-X800 analyzer hybrid cell count system, and the relative integrated density was calculated as number of HMGB1⁺ cells/specimen as shown on Y-axis in the figure. Data are shown as mean ± SD. * Significantly different from normal breast tissue (p < 0.001). (C) BC cell with HMGB1-negative in nucleus and -positive in cytoplasm (top), HMGB1-positive in nucleus and -negative in cytoplasm (middle), and HMGB1-negative in nucleus and -negative in cytoplasm (bottom). (D) Expression of HMGB1 in nucleus (left) and cytoplasm (right) in normal breast tissues (n = 6) and BC (n = 51). Cells expressing HMGB1 in nucleus and cytoplasm in normal breast tissues and BC were counted. Y-axis in the figure indicates as, the percent of cells that express HMGB in the nucleus/cells that express HMGB1 in the cytoplasm and nucleus ×100 (left), and the percent of cells that express HMGB in the cytoplasm/cells that express HMGB1 in the cytoplasm and nucleus ×100 (right). The percent of cells expressing HMGB in the cytoplasm was significantly greater in BCs than normal breast tissues (Fig. 6D, right), while the percent of cells expressing HMGB in the nucleus was not different between BCs and normal breast tissue (Fig. 6D, left). Data are mean ± SD. * Significantly different from normal breast tissue (p < 0.001).