Founder BRCA1 mutations and two novel germline BRCA2 mutations in breast and/or ovarian cancer families from North-Eastern Poland.

Germline mutations in the BRCA1 and BRCA2 genes account for the majority of high-risk breast/ovarian cancer families, depending on the population studied. Previously, BRCA1 mutations were described in women from Western Poland. To further characterize the spectrum of BRCA1 mutations and the impact of BRCA2 mutations in Poland, we have analyzed 25 high-risk breast and/or ovarian cancer families from North-Eastern Poland for mutations in all coding exons of the BRCA1 and BRCA2 genes, using combined heteroduplex analysis/SSCP followed by direct DNA sequence analysis. Out of 25 probands a total of five (20%) carried three recurrent BRCA1 mutations (300T>G, 3819del5, 5382insC). The 300T>G mutation accounted for 60% (3/5) of BRCA1 mutations and allelotyping suggested a common founder of this mutation. No unique mutations were found. In addition, we identified three BRCA2 (12%) mutations, one recurrent 4075delGT, and two novel frameshift mutations, 7327ins/dupl19 and 9068delA. We conclude that 30% of high-risk families from North-Eastern Poland may be due to recurrent BRCA1 and unique BRCA2 mutations. Intriguingly, the BRCA1 mutation spectrum seems to be different within subregions of Poland.

Allelic imbalance and microsatellite instability in BRCA1 associated breast and ovarian tumors.

We have investigated the involvement of microsatellite instability (MSI) and allelic imbalance (AI) at chromosome 13q and 17 in 41 breast and 41 ovarian carcinomas and their association with BRCA1 and BRCA2 gene mutations. MSI was detected in 20% of ovarian and 7% of breast tumors. AI at the BRCA1 locus was detected in 59% and 32% of ovarian and breast tumors, respectively. At the BRCA2 locus, AI rates were 49% and 44% for ovarian and breast tumors, respectively. Germline BRCA1 mutations, identified in 5 (12%) ovarian tumors and in one (2%) breast tumor were not associated with MSI. In only 2/5 BRCA1 positive tumors loss of the wild-type allele was observed. We conclude that BRCA1 mutation status is not associated with MSI and that MSI found in a fraction of ovarian tumors may reflect possible mutations in one of the DNA mismatch repair genes.

Is p53 expression, detected by immunohistochemistry, an important parameter of response to treatment in testis cancer?

BACKGROUND: Several prior studies revealed positive p53 expression via immunohistochemistry (IHC) in a large percentage of germ cell testicular cancers (GCTTs). However, the predicting and prognostic value of this protein remains to be defined. Therefore, the aim of our study was to further clarify the role of p53 protein in GCTTs and to look for correlations between its gene expression and other disease parameters, including histological subtype, stage and clinical resistance sensitivity. Furthermore, we correlated p53 protein expression with that of MDRI gene product protein (Pgp) in order to examine the interrelationship between these two markers. PATIENTS AND METHODS: 77 untreated patients with GCTTs were investigated for their p53 expression using monoclonal antibody and immunohistochemistry in paraffin-embedded specimens. There were 34 patients with stage I, 16 with stage II, 27 with stage III disease. RESULTS: All tumor types, except differentiated teratomas, were immunoreactive for p53 to a various extent ranging from scarcely positive to homogeneously stained tumor cells. Seminomas (S) and embryonal carcinoma (EC) components showed the most positive nuclear staining. p53 expression showed a significant inverse correlation with the stage of disease (P < 0.0003). There was a significant positive relationship between p53 immunoreactivity and response to treatment (P = 0.0012), i.e. high levels of p53 expression correlated with clinical sensitivity of the tumors to chemotherapy. We could demonstrate a statistically significant opposite relationship between p53 and Pgp immunoreactivity (P < 0.0005). CONCLUSION: Our results show that p53 status in tumor cells may be a strong determinate of susceptibility to chemotherapy and that p53 overexpression has a favorable prognosis in terms of response to treatment in GCTTs. Moreover, the findings provide clinical evidence for the presense of significant relationship between p53 and MDR1/Pgp immunoreactivity. They also suggest that patients resistant to chemotherapy and lacking p53 expression might benefit from an alternative appropriately designed chemotherapeutic regimen to achieve further successful treatment in GCTTs.

Vitamin E protects against iron-hexachlorobenzene induced porphyria and formation of 8-hydroxydeoxyguanosine in the liver of C57BL/10ScSn mice.

The effect of vitamin E treatment on total porphyrin content, lipid peroxidation (LOOH) and 8-hydroxydeoxyguanosine (8-OHdG) was studied in the livers of C57BL/10ScSn mice following hexachlorobenzene (HCB) and iron treatment. HCB was administered i.p. (totalling 300 mg/kg) twice, with 1 week interval. Three days after the first HCB injection iron-dextran was given i.p. (500 mg Fe per kg). Vitamin E was administered weekly (20 mg/kg) by s.c. injection. Both total hepatic porphyrin and LOOH levels were significantly (P<0.001) increased in the HCB-iron treated group as compared with the control group. Mice treated additionally with vitamin E had significant (P<0.001) lower levels as compared with the HCB-iron group. Similarly, the levels of 8-OHdG were significantly (P<0.001) increased above controls after HCB-iron treatment and this increase was reduced after co-treatment with vitamin E (P<0.02). The data support the hypothesis that the mechanism of hepatic porphyrinogenicity of HCB with iron overload is an oxidative free radical process.

Effect of silibinin and vitamin E on restoration of cellular immune response after partial hepatectomy.

Our aim was to study the antioxidant and immunomodulatory effect of silibinin and vitamin E on the early postoperative course in rats that had undergone a partial hepatectomy (PHX). Male Wistar rats that were treated with silibinin (50 mg/b.w.kg i.p.) and/or vitamin E (500 mg/b.w.kg p.o.) were randomised to undergo 70% PHX. At 72 h after operation, Concanavalin A (Con-A) induced lymphocyte proliferation, and lipopolysaccharide (LPS) induced interleukin-1 (IL-1) mitogenicity and tumour necrosis factor-alpha (TNF-alpha) cytotoxicity were measured in the spleen. In addition, total free radical scavenger capacity of the liver was analysed. In PHX animals, Con-A induced lymphocyte proliferation was significantly decreased, and both LPS induced IL-1 and TNF-alpha activity were significantly increased as compared to Sham treated animals. Treatment with silibinin and vitamin E synergistically restored both lymphocyte proliferation (P<0.01) and cytokine activity (P<0.001) in PHX animals. In addition, silibinin and vitamin E synergistically (P<0.001) restored total hepatic free radical scavenger capacity as well as serum levels of AST and gammaGT, that were all markedly decreased in PHX animals. Our results suggest that preoperative treatment with silibinin and/or vitamin E modulates the cellular immunoresponse and restores impaired liver function following PHX, presumably through their antioxidant capacity. This may explain their beneficial effects on the postoperative course of liver repair.

Prevalence of founder BRCA1 and BRCA2 mutations among breast and ovarian cancer patients in Hungary.

We have investigated the impact of BRCA1 and BRCA2 mutations that were frequently identified among Hungarian high-risk breast-ovarian cancer families (Ramus et al., 1997b, AJHG), on the development of breast and ovarian cancer in the general Hungarian population. The prevalence of 3 BRCA1 mutations (185delAG, 300T-->G and 5382insC) and 2 BRCA2 mutations (6174delT and 9326insA) was evaluated in a hospital-based consecutive series of 500 female breast cancer patients and 90 ovarian cancer patients, not selected for age at diagnosis or family history of cancer, as well as in 350 controls. Among breast cancer patients, 3.6% (18/500) carried a founder mutation: 9 BRCA1 300T-->G, 7 BRCA1 5382insC, 1 BRCA1 185delAG and 1 BRCA2 9326insA. Among ovarian cancer patients, 11% (10/90) carried a founder mutation: 5 BRCA1 185delAG, 4 BRCA1 300T-->G and 1 BRCA1 5382insC. One control carried a mutation, BRCA1 5382insC. Inherited breast cancer was more frequent among women with younger age at diagnosis: 6.1% of women younger than age 50 but 2.4% of women diagnosed at age 50 or older carried one of the founder mutations. There was no association between mutation status and age at diagnosis of ovarian cancer. Three of 23 medullary breast cancers were inherited (p = 0.038). Carrier status was also associated with a non-significant trend toward advanced tumor stage at diagnosis. These mutations could be evaluated among all ovarian cancer patients and breast cancer patients younger than age 60 and of Hungarian ancestry.

A sporadic breast tumor with a somatically acquired complex genomic rearrangement in BRCA1.

Germ-line mutations in BRCA1 cause a substantial proportion of inherited breast cancer, and most result in inactivated BRCA1 proteins upon translation. Tumours developing in BRCA1 mutation carriers generally show loss of the wild-type allele. However, acquired inactivating mutations in BRCA1 in non-inherited breast tumours showing loss of heterozygosity at the gene locus have not been detected so far. Here we provide evidence that such mutations can be detected in a small proportion of breast tumours. Prompted by recent reports of Alu-mediated large genomic rearrangements in BRCA1, we have investigated whether such rearrangements might occur in sporadic breast cancer as well and have been missed thus far by traditional PCR-based mutation screening technology. To this end, we performed Southern blot analysis of 81 apparently sporadic breast tumours using probes covering exons 6-24 and 3 restriction enzymes. We identified 1 case with an acquired rearrangement (1.2%), indicating that BRCA1 inactivation through changes in the primary genomic sequence of the gene is uncommon in breast cancer. Genes Chromosomes Cancer 27:295-302, 2000.