Expression of MBP-1 and HDAC1 in primary breast tumors and adjacent normal tissues . (A) Representative Western blot analysis of HDAC1, MBP-1 and beta-actin proteins in breast tumors (T) and paired normal tissues (N). (B) HDAC1 protein expression levels in normal versus breast cancer tissues. Proteins were analyzed by immunoblotting and data normalized with respect to beta-actin. The Box plot represents the HDAC1/beta-actin ratio determined in 20 normal tissue (normal), 14 MBP-1-positive (+ve) and 16 MBP-1-negative (−ve) breast tumors. HDAC1 protein levels were associated with MBP-1 status, with a statistically significant enrichment in MBP-1-positive IDCs (4.3 fold, p<0.001). Bars above and below the boxes represent the maximum and minimum expression. Each box delineates the first to third quartiles of expression, and the central bar represents the median. (C) Representative immunohistochemical staining of normal mammary tissue (a-c), MBP-1-positive (#995) and MBP-1-negative (#389) IDC tumors (d-f and g-i, respectively). HDAC1 and MBP-1 nuclear staining in normal tissues (panels a, b) and tumors (panels d, e) correlated with undetectable ErbB2 expression (panels c, f). Magnification: 300x.