p16 and pRb immunohistochemical expression increases with increasing tumour grade in mammary phyllodes tumours

Aims: Control of cell cycling and proliferation is critical to the development of neoplasia and may play a role in the pathogenesis of phyllodes tumours (PTs). This study aimed to evaluate the immunohistochemical expression of certain proteins from the G1 ⁄ S transition of the cell cycle in a cohort of PTs, to determine their role in tumour pathogenesis and to identify any associations with patient outcome. Methods and results: Sixty-five PTs (34 benign, 23 borderline and eight malignant) diagnosed at a single institution between 1990 and 2006 were analysed. Immunohistochemistry for p16, pRb, cyclin D1 and Ki67 was performed. Expression of the following markers increased significantly with tumour grade: stromal nuclear and cytoplasmic p16 (P = 0.01 and 0.002, respectively), stromal and epithelial pRb (P = 0.000 000 06 and 0.004, respectively), and stromal and epithelial Ki67 (P = 0.03 and 0.04, respectively). Epithelial pRb scores of 7 (range 0–7) were significantly associated with reduced disease-free survival (DFS) compared with scores of <7 (P = 0.0009). No relationship was found between cyclin D1 expression in either the epithelium or the stroma, and grade or DFS. Conclusions: The results suggest that alterations at the G1 ⁄ S transition of the cell cycle play an important role in the progression of PTs

Phyllodes tumours of the breast : a clinicopathological analysis of 65 cases from a single institution

The aim of this study was to document the clinical and pathological features of a large single institutional series of ethnically diverse patients with phyllodes tumours (PTs), and to determine which characteristics were predictive of outcome. Sixty five PTs were analysed; 34 were benign, 23 borderline and eight malignant (34 low grade and 31 high grade PTs on a two tiered grading system). Nine patients (15%) had local recurrences. A greater percentage of higher grade tumours recurred and women of Asian origin had a higher recurrence rate compared to the non-Asian patients. The 5 year disease-free survival was 81% and time to recurrence was significantly lower in the high grade group. No metastases or deaths from disease were recorded. The mean age at diagnosis significantly increased with tumour grade. The mean tumour volume also significantly increased with grade. Tumour grade was the only parameter related significantly to outcome

Proteins from the Wnt pathway are involved in the pathogenesis and progression of mammary phyllodes tumours

The Wnt pathway is important in cell signalling transduction and is involved in the pathogenesis of multiple tumour types. A comprehensive analysis of the expression of Wnt signalling pathway proteins in mammary phyllodes tumours (PTs) has not been previously performed. This study aims to evaluate the immunohistochemical expression of Wnt pathway proteins in a cohort of PTs, to determine their role in tumour pathogenesis and to identify any associations with patient outcome. 65 PTs (34 benign, 23 borderline and 8 malignant) diagnosed at a single institution between 1990 and 2006 were analysed. Immunohistochemical stains were performed on tissue microarrays for b-catenin, Wnt1, Wnt5a, SFRP4 and E-cadherin. Stroma and epithelium were scored separately. Stromal cytoplasmic Wnt5a and SFRP4 expression showed significant progressive increases in expression with increasing grade (p=0.002 and p=0.02 respectively). Epithelial membranous and stromal nuclear b-catenin, epithelial cytoplasmic Wnt1 and epithelial E-cadherin all also showed increasing expression with increasing tumour grade, however, the differences were not significant. Disease-free survival was significantly decreased (p=0.0017) with positive epithelial Ecadherin staining. Results suggest that alterations in the Wnt pathway are important in the progression and in the epithelial and stromal interactions in PTs. They have important implications for understanding the pathogenesis of these uncommon but clinically important tumours

Inflammasome-dependent IFN-γ drives pathogenesis in Streptococcus pneumoniae meningitis

The pathology associated with Streptococcus pneumoniae meningitis results largely from activation of immune-associated pathways. We systematically investigated the production of IFN subtypes, as well as their influence on pathology, in a mouse model of S. pneumoniae meningitis. Despite the occurrence of a mixed IFN type I/II gene signature, no evidence for production or involvement of type I IFNs in disease progression was found. In contrast, type II IFN (IFN-γ) was strongly induced, and IFN-γ(-/-) mice were significantly protected from severe disease. Using intracellular cytokine staining and targeted cell-depletion approaches, NK cells were found to be the dominant source of IFN-γ. Furthermore, production of IFN-γ was found to be dependent upon ASC and IL-18, indicating that an ASC-dependent inflammasome pathway was responsible for mediating IFN-γ induction. The influence of IFN-γ gene deletion on a range of processes known to be involved in bacterial meningitis pathogenesis was examined. Although neutrophil numbers in the brain were similar in infected wild-type and IFN-γ(-/-) mice, both monocyte recruitment and CCL2 production were less in infected IFN-γ(-/-) mice compared with infected wild-type controls. Additionally, gene expression of NO synthase was strongly diminished in infected IFN-γ(-/-) mice compared with infected controls. Finally, bacterial clearance was enhanced in IFN-γ(-/-) mice, although the underlying mechanism remains unclear. Together, these data suggest that inflammasome-dependent IFN-γ contributes via multiple pathways to pathology during S. pneumoniae meningitis

BRAF Mutation, NRAS Mutation, and the Absence of an Immune-Related Expressed Gene Profile Predict Poor Outcome in Patients with Stage III Melanoma

Prediction of outcome for melanoma patients with surgically resected macroscopic nodal metastases is very imprecise. We performed a comprehensive clinico-pathologic assessment of fresh-frozen macroscopic nodal metastases and the preceding primary melanoma, somatic mutation profiling, and gene expression profiling to identify determinants of outcome in 79 melanoma patients. In addition to disease stage <II at initial presentation, the following clinical and pathologic factors were independent predictors of improved outcome (odds ratios for survival >4 years, 90% confidence interval): the presence of a nodular component in the primary melanoma (6.8, 0.6–76.0), and small cell size (11.1, 0.8–100.0) or low pigmentation (3.0, 0.8–100.0) in the nodal metastases. Absence of BRAF mutation (20.0, 1.0–1000.0) or NRAS mutation (16.7, 0.6–1000.0) were both favorable prognostic factors. A 46-gene expression signature with strong overrepresentation of immune response genes was predictive of better survival (10.9, 0.4–325.6); in the full cohort, median survival was >100 months in those with the signature, but 10 months in those without. This relationship was validated in two previously published independent stage III melanoma data sets. We conclude that the presence of BRAF mutation, NRAS mutation, and the absence of an immune-related expressed gene profile predict poor outcome in melanoma patients with macroscopic stage III disease

The Yeast Homolog of Heme Oxygenase-1 Affords Cellular Antioxidant Protection via the Transcriptional Regulation of Known Antioxidant Genes*

Heme oxygenase-1 (HO-1) degrades heme and protects cells from oxidative challenge. This antioxidant activity is thought to result from the HO-1 enzymatic activity, manifested by a decrease in the concentration of the pro-oxidant substrate heme, and an increase in the antioxidant product bilirubin. Using a global transcriptional approach, and yeast as a model, we show that HO-1 affords cellular protection via up-regulation of transcripts encoding enzymes involved in cellular antioxidant defense, rather than via its oxygenase activity. Like mammalian cells, yeast responds to oxidative stress by expressing its HO-1 homolog and, compared with the wild type, heme oxygenase-null mutant cells have increased sensitivity toward oxidants that is rescued by overexpression of human HO-1 or its yeast homolog. Increased oxidant sensitivity of heme oxygenase-null mutant cells is explained by a decrease in the expression of the genes encoding γ-glutamylcysteine synthetase, glutathione peroxidase, catalase, and methionine sulfoxide reductase, because overexpression of any of these genes affords partial, and overexpression of all four genes provides complete, protection to the null mutant. Genes encoding antioxidant enzymes represent only a small portion of the 480 differentially expressed transcripts in heme oxygenase-null mutants. Transcriptional regulation may be explained by the nuclear localization of heme oxygenase observed in oxidant-challenged cells. Our results challenge the notion that HO-1 functions simply as a catabolic and antioxidant enzyme. They indicate much broader functions for HO-1, the unraveling of which may help explain the multiple biological responses reported in animals as a result of altered HO-1 expression