Chromosome alterations and E-cadherin gene mutations in human lobular breast cancer

We have studied a set of 40 human lobular breast cancers for loss of heterozygosity (LOH) at various chromosome locations and for mutations in the coding region plus flanking intron sequences of the E-cadherin gene. We found a high frequency of LOH (100%, 31/31) at 16q21–q22.1. A significantly higher level of LOH was detected in ductal breast tumours at chromosome arms 1p, 3p, 9p, 11q, 13q and 18q compared to lobular breast tumours. Furthermore, we found a significant association between LOH at 16 q containing the E-cadherin locus and lobular histological type. Six different somatic mutations were detected in the E-cadherin gene, of which three were insertions, two deletions and one splice site mutation. Mutations were found in combination with LOH of the wild type E-cadherin locus and loss of or reduced E-cadherin expression detected by immunohistochemistry. The mutations described here have not previously been reported. We compared LOH at different chromosome regions with E-cadherin gene mutations and found a significant association between LOH at 13 q and E-cadherin gene mutations. A significant association was also detected between LOH at 13q and LOH at 7q and 11q. Moreover, we found a significant association between LOH at 3 p and high S phase, LOH at 9p and low ER and PgR content, LOH at 17p and aneuploidy. We conclude that LOH at 16q is the most frequent chromosome alteration and E-cadherin is a typical tumour suppressor gene in lobular breast cancer. © 1999 Cancer Research Campaig

Altered expression of E-cadherin in breast cancer patterns, mechanisms and clinical significance

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldReduced cell adhesion brought about by altered surface expression of E-cadherin has been implicated in invasive and metastatic malignant growth. We investigated the patterns of immunohistochemical E-cadherin expression in 120 breast carcinomas. Furthermore, we analysed DNA from the same samples for loss of heterozygosity (LOH) using three separate microsatellite markers on chromosome 16q22.1. Finally, the clinical outcome was ascertained for 108 patients. 19% (18/97) of infiltrating ductal carcinomas showed complete loss of E-cadherin expression compared with 64% (9/14) of infiltrating lobular carcinomas. LOH was detected in 46% (24/52) of infiltrating ductal carcinomas and 89% (8/9) of infiltrating lobular carcinomas. In the infiltrating lobular carcinomas, LOH was associated with complete loss of cell membrane expression of E-cadherin, although a cytoplasmic expression pattern was evident. In contrast, this association was not seen in the infiltrating ductal carcinomas. In a multivariate analysis, loss of E-cadherin expression was shown to be a significant independent risk factor for a poorer disease-free survival (P=0.019), in particular in the node-negative subset of patients (P=0.029). Significance was also approached for breast cancer corrected survival (P=0.056). We conclude that different mechanisms are involved in the altered E-cadherin expression seen in different subtypes of breast carcinomas. Furthermore, we implicate loss of E-cadherin, regardless of the genetic causes, as an independent prognostic marker for disease recurrence, especially in node-negative breast cancer patients, irrespective of the histological type

Iceland's meltdown: the rise and fall of international banking in the North Atlantic

This paper shows how rapid privatization and liberalization of Iceland's small local banks around 2000, combined with well-developed crony relations among the elite, enabled a small group of financiers to leverage government-guaranteed deposits into a vast wave of mergers and acquisitions abroad, and redistribute enough of the profits back home to make the economy boom. Negative policy feedback loops were systematically undermined. The incoming left-wing government, with IMF support, has managed to protect the bulk of the population from the worst of the effects