Effect of habitat fragmentation on levels and patterns of genetic diversity in natural populations of the peat moss Polytrichum commune

Peat bogs represent unique ecosystems that are under particular threat from fragmentation due to peat harvesting, with only 38% of the original peatland in Europe remaining intact and unaffected by peat cutting, drainage and silviculture. In this study, we have used microsatellite markers to determine levels and patterns of genetic diversity in both cut and uncut natural populations of the peat moss Polytrichum commune. Overall diversity levels suggest that there is more genetic variation present than had previously been assumed for bryophytes. Despite this, diversity values from completely cut bogs were found to be lower than those from uncut peatlands (average 0.729 versus 0.880). In addition, the genetic diversity was more highly structured in the cut populations, further suggesting that genetic drift is already affecting genetic diversity in peat bogs subjected to fragmentation

Prohibitin expression is associated with high grade breast cancer but is not a driver of amplification at 17q21.33

Aims: In a study of ductal carcinoma in situ of the breast, we identified five genes at chromosome 17q21.33 that were over-expressed in high grade cases, and showed a correlation between expression and gene copy number. The aim of this study was to investigate potential drivers of genomic amplification at 17q21.33. Methods: Analysis of high resolution comparative genomic hybridisation and published data specified a minimum region of amplification at 17q21.33. Prohibitin (PHB) expression was examined by immunohistochemistry in 285 invasive breast cancers. Gene copy number was examined by fluorescence in situ hybridisation. Results: The minimum region of amplification at 17q21.33 included ten genes with PHB selected as a candidate driver. Increased PHB expression was associated with higher grade breast cancer and poorer survival. Amplification of PHB was detected in 13 of 235 cases (5.5%) but was not associated with PHB expression. PHB amplification was most common in the ERBB2+ breast cancer subtype, although high expression was most prevalent in basal-like and luminal B cancers. Conclusions: Amplification at 17q21.33 is a recurrent feature of breast cancer that forms part of a 'firestorm' pattern of genomic aberration. PHB is not a driver of amplification, however PHB may contribute to high grade breast cancer

Poor-prognosis estrogen receptor-positive breast cancer identified by histopathologic subclassification

Purpose: Identification of biologically and clinically distinct breast cancer subtypes could improve prognostic assessment of primary tumors. The characteristics of ''molecular'' breast cancer subtypes suggest that routinely assessed histopathologic features in combination with limited biomarkers may provide an informative classification for routine use. Experimental Design: Hierarchical cluster analysis based on components of histopathologic grade (tubule formation, nuclear pleomorphism, and mitotic score), expression of ER, cytokeratin 5/6, and HER2 amplification identified four breast cancer subgroups in a cohort of 270 cases. Cluster subgroup membership was compared with observed and Adjuvant! Online predicted 10-year survival. Survival characteristics were confirmed in an independent cohort of 300 cases assigned to cluster subgroups using a decision tree model. Results: Four distinct breast cancer cluster subgroups (A-D) were identified that were analogous to molecular tumor types and showed a significant association with survival in both the original and validation cohorts (