Post-translational histone modifications are known to be altered in cancer cells, and loss of selected histone acetylation and methylation marks has recently been shown to predict patient outcome in human carcinoma. Immunohistochemistry was used to detect a series of histone lysine acetylation (H3K9ac, H3K18ac, H4K12ac, and H4K16ac), lysine methylation (H3K4me2 and H4K20me3), and arginine methylation (H4R3me2) marks in a well-characterized series of human breast carcinomas (n = 880). Tissue staining intensities were assessed using blinded semiquantitative scoring. Validation studies were done using immunofluorescence staining and Western blotting. Our analyses revealed low or absent H4K16ac in the majority of breast cancer cases (78.9%), suggesting that this alteration may represent an early sign of breast cancer. There was a highly significant correlation between histone modifications status, tumor biomarker phenotype, and clinical outcome, where high relative levels of global histone acetylation and methylation were associated with a favorable prognosis and detected almost exclusively in luminal-like breast tumors (93%). Moderate to low levels of lysine acetylation (H3K9ac, H3K18ac, and H4K12ac), lysine (H3K4me2 and H4K20me3), and arginine methylation (H4R3me2) were observed in carcinomas of poorer prognostic subtypes, including basal carcinomas and HER-2-positive tumors. Clustering analysis identified three groups of histone displaying distinct pattern in breast cancer, which have distinct relationships to known prognostic factors and clinical outcome. This study identifies the presence of variations in global levels of histone marks in different grades, morphologic types, and phenotype classes of invasive breast cancer and shows that these differences have clinical significance. [Cancer Res 2009;69(9):3802-9]

Background: The keratinocytic hyperproliferative lesions include non-tumorigenic, pre-tumorigenic (actinic keratoses, AK), and tumorigenic (squamous cell carcinomas, SCC) conditions. Although mononuclear inflammatory cell infiltrate (MICs) is a constant feature in these lesions, their immunophenotypic characterization is still incomplete. We hypothesized that the development of non-tumorigenic, pre-tumorigenic, and tumorigenic keratinocytic hyperproliferative lesions is associated with alterations in the mononuclear inflammatory cell infiltrate in response to altered antigenicity of the lesional cells. This study tries to test this hypothesis and to characterize MICs in these lesions.Methods: Fifty lesions (non-tumorigenic lesions, 29; AK, 9 and SCC, 12) were examined using immunoperoxidase staining methods and antibodies targeting histiocytes (CD68), T cells (CD3), B cells (CD20), and T cells with cytotoxic potential (TIA-1).Results: As compared to the normal skin, the development of the keratinocytic hyperproliferative lesions (normal skin; non-tumorigenic; AK and SCC) was associated with a statistically significant increase(p = <0.05) in: (1) CD20 + B lymphocytes (0.0 ± 0.0 vs. 3.1 ± 0.5 vs. 7.5 ± 0.3 vs. 14.5 ± 5.5); (2) CD68 histiocytes (4.0 ± 1.0 vs. 26.5 ± 3.9 vs. 23 ± 1.9 vs. 41.3 ± 6.8); (3) CD3 + T lymphocytes (3.0 ± 1.1 vs. 58.3 ± 10.3 vs. 54.5 ± 0.2 vs. 41.0 ± 16.0); and (4) TIA-1 + cytotoxic T cells (1.8 ± 0.4 vs. 2.9 ± 0.7 vs. 9.6 ± 1.1 vs. 13.7 ± 5.2).Conclusions: The increase in the number of infiltrating mononuclear cells in all pathologic lesions compared to normal skin may reflect increased antigenicity of the lesional cells. Both humoral and cell mediated immunity are involved in these lesions.