Mutations of the BRCA1 and BRCA2 genes in patients with bilateral breast cancer

Mutations of the BRCA1 or BRCA2 genes have been shown to strongly predispose towards the development of contralateral breast cancer in patients from large multi-case families. In order to test the hypothesis that BRCA1 and BRCA2 mutations are more frequent in patients with bilateral breast cancer, we have investigated a hospital-based series of 75 consecutive patients with bilateral breast cancer and a comparison group of 75 patients with unilateral breast cancer, pairwise matched by age and family history, for mutations in the BRCA1 and BRCA2 genes. Five frameshift deletions (517delGT in BRCA1; 4772delA, 5946delCT, 6174delT and 8138del5 in BRCA2) were identified in patients with bilateral disease. No further mutations, apart from polymorphisms and 3 rare unclassified variants, were found after scanning the whole BRCA1 and BRCA2 coding sequence. Three pathogenic BRCA1 mutations (Cys61Gly, 3814del5, 5382insC) were identified in the group of patients with unilateral breast cancer. The frequencies of common BRCA1 and BRCA2 missense variants were not different between the 2 groups. In summary, we did not find a significantly increased prevalence of BRCA1 and BRCA2 mutations in a hospital-based cohort of German patients with bilateral breast cancer. We conclude that bilaterality of breast cancer on its own is not strongly associated with BRCA1 and BRCA2 mutations when adjusted for age and family history. The high frequency of bilateral disease in multi-case breast cancer families may be due to a familial aggregation of additional susceptibility factors modifying the penetrance of BRCA1 and BRCA2 mutations. © 2001 Cancer Research Campaignhttp://www.bjcancer.co

Analysis of colloids VIII. Concentration and memory effects in size exclusion chromatography of colloidal inorganic nanometer particles

Colloidal cadmium sulfide with diameters of ca. 17 nm was used as a model substance to study the effects of sample concentration on elution time and peak area in size exclusion chromatography SEC of colloidal inorganic particles in the low nm size regime. A clear distinction had to be made between the pure particle concentration and that of the accompanying electrolytes. The effects were astonishingly high taking into account that particles and small electrolytes are separated immediately in SEC. The reasons for these phenomena are discussed. The electrical double layer was found to play an important role. The results obtained for solid particles were compared with those for organic polymers in SEC. A memory effect of the column was observed due to temporarily adsorbed particle

Steric exclusion chromatography of nanometersized gold particles

It is shown that steric exclusion chromatography can be used to measure the size distribution of colloidal gold sols. Good separation can be achieved for particles ranging in size from 3.0 to 20 nm using columns containing 25 mum silica particles pore size 50 100 nm and with aqueous trisodium citrate 0.001 M as the eluen