Some patients with childhood membranous nephropathy have both circulating cationic bovine serum albumin and anti-bovine serum albumin antibodies. Bovine serum albumin is present in immune deposits, suggesting that cationic bovine serum albumin is pathogenic through binding to the anionic glomerular capillary wall and in situ formation of immune complexes, as shown in experimental models.

The Epstein-Barr virus (EBV) has been detected in subsets of breast cancers. In order to elaborate on these observations, we quantified by real-time PCR (Q-PCR) the EBV genome in biopsy specimens of breast cancer tissue as well as in tumor cells isolated by microdissection. Our findings show that EBV genomes can be detected by Q-PCR in about half of tumor specimens, usually in low copy numbers. However, we also found that the viral load is highly variable from tumor to tumor. Moreover, EBV genomes are heterogeneously distributed in morphologically identical tumor cells, with some clusters of isolated tumor cells containing relatively high genome numbers while other tumor cells isolated from the same specimen may be negative for EBV DNA. Using reverse transcription-PCR, we detected EBV gene transcripts: EBNA-1 in almost all of the EBV-positive tumors and RNA of the EBV oncoprotein LMP-1 in a smaller subset of the tissues analyzed. Moreover, BARF-1 RNA was detected in half of the cases studied. Furthermore, we observed that in vitro EBV infection of breast carcinoma cells confers resistance to paclitaxel (taxol) and provokes overexpression of a multidrug resistance gene (MDR1). Consequently, even if a small number of breast cancer cells are EBV infected, the impact of EBV infection on the efficiency of anticancer treatment might be of importance.The Epstein-Barr virus (EBV), a ubiquitous human herpesvirus, is associated with the development of different epithelial malignancies (28), including nasopharyngeal carcinoma (NPC). It has also been linked with subsets of other types of carcinomas, including gastric carcinoma and lymphoepithelioma-like carcinoma in salivary glands and thymus (32,44). Several laboratories have reported detection of EBV in a subset of breast tumors (3,10,19,23). However, negative results have also been reported (6,9,14,27). Nevertheless, in most of the studies, a low viral load was detected in breast cancer biopsy specimens but the infected cells were not clearly identified. In the study presented here, we used real-time PCR (Q-PCR) to quantify the copy numbers of the EBV genome in biopsy specimens as well as in microdissected tumor cells. The results show that breast cancer cells harbor the viral genome. However, through microdissection and isolation of pure tumor cells, we now find that even in EBV-positive tumor samples, many tumor cells do not contain EBV genomes and that the breast carcinomas are highly heterogeneous in terms of genome content and distribution. Moreover, using reverse transcription-PCR (RT-PCR), we detected EBNA-1 and BARF-1 transcripts in almost all of the EBV-positive tumors and LMP-1 RNA in 3 of the 15 cases studied. The findings raise the possibility that although EBV is unlikely to have an etiologic role in the genesis of breast cancer, the virus might contribute to tumor progression. Finally, the potential impact of EBV in breast cancer progression was evaluated by estimation of resistance to chemotherapeutic agents on in vitro-infected MDA-MB-231 cells. The resul...

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