[Prevention in familial breast cancer susceptibility]

First retrospective data show that hereditary Breast cancer risk can be positively influenced by prophylactic surgical procedures and hereby a thorough consultation seem to be an option for mutant gene carriers. A first evaluation of the women of 1050 high-risk families by the German Consortium "Hereditary Breast and Ovarian Cancer promoted by the German Cancer Aid (Deutsche Krebshilfe)" has shown that approximately 80% of the women concerned decide to participate in an intensive early detection--programme and only 5% of the women have decided to submit themselves to prophylactic surgical measures. This again shows how absolutely necessary the elaboration and evaluation of early detection measures within the different investigation projects are.

Characterization of the human Rad51 genomic locus and examination of tumors with 15q14-15 loss of heterozygosity (LOH)

Human Rad51 (hRad51) has been found to be associated with BRCA1, BRCA2, and p53 either directly or indirectly and is one of at least eight human genes that are members of the Escherichia coli RecA/Saccharomyces cerevisiae Rad51 family thought to affect genomic stability through DNA recombination/repair processes. While inactivation of DNA mismatch repair clearly leads to instability of repeated sequences and to an increased risk for tumorigenesis, such a parallel for the RecA family members has not been reported. Recently, a high frequency of loss of heterozygosity at chromosome 15q14-15, near the genomic region containing hRad51, has been reported in human tumors (W. Wick et al., Oncogene, 12: 973-978, 1996). To determine whether hRad51 inactivation may be involved in the etiology of these tumors, we have characterized the hRad51 genetic locus and mapped it to chromosome 15q14-15 within the central region of loss of heterozygosity. However, single-strand conformational polymorphism analysis and direct sequencing of tumors did not reveal any mutations in the hRad51 coding sequence or intron/exon boundaries. We also examined the DNA methylation status of a CpG-rich region in the putative hRad51 promoter region. No indication of hypermethylation was found. These results suggest that hRad51 is not a tumor suppressor because it is either an essential gene, redundant gene and/or independent of the BRCA1/BRCA2 tumor suppressor pathway(s).

Anti-EBNA-1 (carboxy-half) IgG antibodies as a seroepidemiological marker for Epstein-Barr virus infection

A population of 2,024 voluntary blood donors was tested for anti-EBNA-1 IgG and anti-VCA IgG serum antibodies to define the EBV infection rate and to compare two different epidemiological markers. Initial screening was performed with a sensitive EBNA-1-IgG ELISA based on recombinant antigen (Biotest) and a VCA-IgG ELISA based on conventional antigen. Both ELISAs had concordant results in 90.4% of the sera. The infection rate was found to be 96.8%. The expected immune status VCA+/EBNA+ was observed in 98.1% of the seropositives. The comparison of sensitivity, specificity, and predictive values between the two screening assays underlines the superiority of the EBNA-1 ELISA. The marker anti-EBNA-1 IgG as detected by a sensitive ELISA (Biotest anti-EBV recombinant) is suitable for defining previous EBV infection (positive predictive value 99.8%). The high infection rate in the adult population, however, renders the supply with EBV-negative blood rather difficult.