A, left panel,immunohistochemical staining of HDAC6 in ovarian tumors. Representative examples of intense HDAC6 staining of high-grade and low-grade ovarian serous carcinomas and weaker staining in serous adenofibroma and serous cystadenoma (imaging with X40 objective), right panel, staining intensity for each case was graded as 0 (no staining), 1 (weak staining), 2 (moderate staining) and 3 (intense staining), and the statistical significance of differences in staining intensities among indicated groups was calculated using the Mann-Whitney U test. Error bars indicate ± SD. B, Western blot analysis of HDAC6 in clinical specimens of serous cystadenoma (lanes 1–4) and serous carcinoma (lanes 5–10). Equal loading was verified by using an antibody directed against β-actin. C, Western blot analysis of HDAC6 immortalized ovarian surface epithelial cells (IOSE-29 and IOSE-397) and ovarian cancer cell lines (SKOV-3, ES-2, TOV-21G). Equal protein loading in each lane was verified by using an antibody directed against β-actin.