Tamar Peretz

A single-nucleotide polymorphism in the RAD51 gene modifies breast cancer risk in BRCA2 carriers, but not in BRCA1 carriers or noncarriers

Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. The RAD51 gene, which participates in homologous recombination double-strand breaks (DSB) repair in the same pathway as the BRCA1 and BRCA2 gene products, is a candidate for such an effect. A single-nucleotide polymorphism (SNP), RAD51-135g → c, in the 5′ untranslated region of the gene has been found to elevate breast cancer (BC) risk among BRCA2 carriers. We genotyped 309 BRCA1/2 mutation carriers, of which 280 were of Ashkenazi origin, 166 noncarrier BC patients and 152 women unaffected with BC (a control group), for the RAD51-135g → c SNP. Risk analyses were conducted using COX proportional hazard models for the BRCA1/2 carriers and simple logistic regression analysis for the noncarrier case–control population. BRCA2 carriers were also studied using logistic regression and Kaplan–Meier survival analyses. The estimated BC hazard ratio (HR) for RAD51-135c carriers adjusted for origin (Ashkenazi vs non-Ashkenazi) was 1.28 (95% CI 0.85–1.90, P=0.23) for BRCA1/2 carriers, and 2.09 (95% CI 1.04–4.18, P=0.04) when the analysis was restricted to BRCA2 carriers. The median BC age was younger in BCRA2-RAD51-135c carriers (45 (95% CI 36–54) vs 52 years (95% CI 48–56), P=0.05). In a logistic regression analysis, the odds ratio (OR) was 5.49 (95% CI 0.5–58.8, P=0.163). In noncarrier BC cases, carrying RAD51-135c was not associated with BC risk (0.97; 95% CI 0.47–2.00). These results indicate significantly elevated risk for BC in carriers of BRCA2 mutations who also carry a RAD51-135c allele. In BRCA1 carriers and noncarriers, no effect for this SNP was found.

CAG and GGC repeat polymorphisms in the androgen receptor gene and breast cancer susceptibility in BRCA1/2 carriers and non-carriers

Variation in the penetrance estimates for BRCA1 and BRCA2 mutations carriers suggests that other genetic polymorphisms may modify the cancer risk in carriers. A previous study has suggested that BRCA1 carriers with longer lengths of the CAG repeat in the androgen receptor (AR) gene are at increased risk of breast cancer (BC). We genotyped 188 BRCA1/2 carriers (122 affected and 66 unaffected with breast cancer), 158 of them of Ashkenazi origin, 166 BC cases without BRCA1/2 mutations and 156 Ashkenazi control individuals aged over 56 for the AR CAG and GGC repeats. In carriers, risk analyses were conducted using a variant of the log-rank test, assuming two sets of risk estimates in carriers: penetrance estimates based on the Breast Cancer Linkage Consortium (BCLC) studies of multiple case families, and lower estimates as suggested by population-based studies. We found no association of the CAG and GGC repeats with BC risk in either BRCA1/2 carriers or in the general population. Assuming BRCA1/2 penetrance estimates appropriate to the Ashkenazi population, the estimated RR per repeat adjusted for ethnic group (Ashkenazi and non-Ashkenazi) was 1.05 (95%CI 0.97–1.17) for BC and 1.00 (95%CI 0.83–1.20) for ovarian cancer (OC) for CAG repeats and 0.96 (95%CI 0.80–1.15) and 0.90 (95%CI 0.60–1.22) respectively for GGC repeats. The corresponding RR estimates for the unselected case–control series were 1.00 (95%CI 0.91–1.10) for the CAG and 1.05 (95%CI 0.90–1.22) for the GGC repeats. The estimated relative risk of BC in carriers associated with ≥28 CAG repeats was 1.08 (95%CI 0.45–2.61). Furthermore, no significant association was found if attention was restricted to the Ashkenazi carriers, or only to BRCA1 or BRCA2 carriers. We conclude that, in contrast to previous observations, if there is any effect of the AR repeat length on BRCA1 penetrance, it is likely to be weak.

Synergistic inhibitory effects of genistein and tamoxifen on human dysplastic and malignant epithelial breast cells in vitro.

OBJECTIVEnGenistein is a phytoestrogen with in vitro anticancerogenic activity. We examined in vitro the effects of genistein alone, or in combination with estradiol and tamoxifen, on the growth of human dysplastic and malignant epithelial breast cell lines.nnnMETHODSnDysplastic breast cell lines (MCF-10A(1), MCF-ANeoT, MCF-T(6)3B) and cell lines of breast cancer (MCF-7, MDA-231, MDA-435) were cultured as monolayers in RPMI 1640 medium supplemented with 10% fetal bovine serum, and L-glutamine. After preincubation of 20 h, genistein (1, 2.5, 5, 7.5 and 10 microg/ml) alone or in combination with estrogen or tamoxifen was added to the cultured cells. The cells were treated continuously for 72 h and then the growth rate was assessed colorimetrically. Stepwise multiple linear regression analysis was used to evaluate the effect of genistein, tamoxifen, and estradiol on cell proliferation.nnnRESULTSnGenistein had a significant (dose-dependent) inhibitory effect on the proliferation of both dysplastic (P<0.0001) and malignant (P<0.0001) cells. The growth inhibition was significantly higher P<0.0001 in dysplastic cells compared to the cancer cells. Addition of tamoxifen to genistein further inhibited the proliferation of both cell types, reflecting a synergistic antiproliferative effect on dysplastic cells P<0.0001 and an additive growth inhibition effect P<0.0003 on malignant cells. Estradiol significantly (P=0.005) stimulated the growth of dysplastic cell lines while a significant (P=0.003) antiproliferative effect on growth of the malignant cells was observed. The concentration of estrogen receptor (ER) had no significant effect on growth rates and did not modulate the effects of genistein or tamoxifen.nnnCONCLUSIONSnGenistein (1-10 microg/ml) inhibits the growth of dysplastic and malignant epithelial breast cancer cells in vitro and the addition of tamoxifen (10(-6), 10(-7)M) has a synergistic/additive inhibitory effect. These effects are not modulated by the presence of ER.

Psychological distress in female cancer patients with Holocaust experience

This study examined whether severe emotional and physical trauma in the past affects the psychological condition of female patients currently afflicted with cancer. Using the Brief Symptom Inventory (BSI), 41 women with cancer, who had sustained extreme trauma during the Nazi Holocaust of the midcentury, were compared with three different groups: a matched group of cancer patients without Holocaust experience, a physically healthy group of female Holocaust survivors, and healthy women without a Holocaust past. Although psychological distress was comparable in the two healthy groups, it was far higher in Holocaust cancer patients than in either their non-Holocaust counterparts or in the group of healthy Holocaust survivors. These results may suggest that the severe trauma of the Holocaust could be responsible for markedly diminished psychological response when such patients are confronted with new stress.

Polyglutamine repeat length in the AIB1 gene modifies breast cancer susceptibility in BRCA1 carriers

Variation in the penetrance estimates for BRCA1 and BRCA2 mutation carriers suggests that other factors may modify cancer risk from specific mutations. One possible mechanism is an epigenetic effect of polymorphisms in other genes. Genes involved in hormonal signal transduction are possible candidates. The AIB1 gene, an estrogen receptor (ER) coactivator, is frequently amplified in breast and ovarian tumors. Variation of a CAG repeat length has been reported within this gene that encodes a polyglutamine repeat in the C‐terminus of the protein. Three hundred eleven BRCA1/2 mutation carriers (257 were of Ashkenazi origin) were genotyped for the AIB1 polyglutamine repeat. Relative risks (RR) were estimated using a maximum likelihood approach. The estimated breast cancer (BC) RR per average repeat length adjusted for population type (Ashkenazi vs. non‐Ashkenazi) was 1.15 (95% CI = 1.02–1.30; p = 0.01) for BRCA1/2 carriers, and 1.25 (95% CI = 1.09–1.42; p = 0.001) when analysis was restricted to BRCA1 carriers. RR of BC was 1.17 (95% CI = 0.91–1.74), for individuals with 2 alleles ≥29 polyglutamine repeats and 0.78 (95% CI = 0.50–1.16) for those with at least 1 allele of ≤26 repeats, compared to individuals with the common genotypes 28;28, 28;29 or 28;30. The corresponding BC RR in BRCA1 mutation carriers was 0.55 (95% CI = 0.34–0.90) and 1.29 (95% CI = 0.85–1.96) in those with ≤26 and ≥29 repeats respectively (p = 0.025). These results indicate significant association of the risk for BC in carriers of BRCA1 mutations with the polyglutamine chain of the AIB1 gene. Longer repeat length correlates with elevated risk, whereas in carriers of a shorter AIB1 allele BC risk was reduced. The AIB1 polyglutamine length did not affect BC risk among BRCA2 mutation carriers.

A novel BRCA-1 mutation in Arab kindred from east Jerusalem with breast and ovarian cancer.

BackgroundThe incidence of breast cancer (BC) in Arab women is lower compared to the incidence in the Jewish population in Israel; still, it is the most common malignancy among Arab women. There is a steep rise in breast cancer incidence in the Arab population in Israel over the last 10 years that can be attributed to life style changes. But, the younger age of BC onset in Arab women compared with that of the Jewish population is suggestive of a genetic component in BC occurrence in that population.MethodsWe studied the family history of 31 women of Palestinian Arab (PA) origin affected with breast (n = 28), ovarian (n = 3) cancer. We used denaturing high performance liquid chromatography (DHPLC) to screen for mutations of BRCA1/2 in 4 women with a personal and family history highly suggestive of genetic predisposition.ResultsA novel BRCA1 mutation, E1373X in exon 12, was found in a patient affected with ovarian cancer. Four of her family members, 3 BC patients and a healthy individual were consequently also found to carry this mutation. Of the other 27 patients, which were screened for this specific mutation none was found to carry it.ConclusionWe found a novel BRCA1 mutation in a family of PA origin with a history highly compatible with BRCA1 phenotype. This mutation was not found in additional 30 PA women affected with BC or OC. Therefore full BRCA1/2 screening should be offered to patients with characteristic family history. The significance of the novel BRCA1 mutation we identified should be studied in larger population. However, it is likely that the E1373X mutation is not a founder frequent mutation in the PA population.

Glutathione-S-transferase M1, T1 and P1 polymorphisms, and breast cancer risk, in BRCA1/2 mutation carriers

Variation in penetrance estimates for BRCA1/2 carriers suggests that other environmental and genetic factors may modify cancer risk in carriers. The GSTM1, T1 and P1 isoenzymes are involved in metabolism of environmental carcinogens. The GSTM1 and GSTT1 gene is absent in a substantial proportion of the population. In GSTP1, a single-nucleotide polymorphism that translates to Ile112Val was associated with lower activity. We studied the effect of these polymorphisms on breast cancer (BC) risk in BRCA1/2 carriers. A population of 320 BRCA1/2 carriers were genotyped; of them 262 were carriers of one of the three Ashkenazi founder mutations. Two hundred and eleven were affected with BC (20 also with ovarian cancer (OC)) and 109 were unaffected with BC (39 of them had OC). Risk analyses were conducted using Cox proportional hazard models adjusted for origin (Ashkenazi vs non-Ashkenazi). We found an estimated BC HR of 0.89 (95% CI 0.65–1.12, P=0.25) and 1.11 (95% CI 0.81–1.52, P=0.53) for the null alleles of GSTM1 and GSTT1, respectively. For GSTP1, HR for BC was 1.36 (95% CI 1.02–1.81, P=0.04) for individuals with Ile/Val, and 2.00 (95% CI 1.18–3.38) for carriers of the Val/Val genotype (P=0.01). An HR of 3.20 (95% CI 1.26–8.09, P=0.01), and younger age at BC onset (P=0.2), were found among Val/Val, BRCA2 carriers, but not among BRCA1 carriers. In conclusion, our results indicate significantly elevated risk for BC in carriers of BRCA2 mutations with GSTP1-Val allele with dosage effect, as implicated by higher risk in homozygous Val carriers. The GSTM1- and GSTT1-null allele did not seem to have a major effect.

Genetic predisposition to radiation induced sarcoma: possible role for BRCA and p53 mutations

The estimated incidence of radiation-associated sarcoma (RAS) is 0.03–0.2xa0% in 5xa0years post treatment. Most cancer predisposing genes are involved in DNA repair; therefore, elevated RAS risk in these patients is plausible. Cases of angiosarcoma post breast cancer treatment were reported in BRCA1 and BRCA2 carriers. We report the genetic evaluation of seven cases with suspected RAS from patients counseled in our cancer-genetic clinic. Of 2,885 breast cancer patient, 470 were BRCA1 or two mutation carriers and three were p53 mutation carriers. Of them seven developed sarcoma in the field of irradiation; five in the chest wall and two in other sites. Genetic evaluation revealed BRCA1 mutation in two, BRCA2 mutation in additional patient and a carrier of p53 mutation. The estimation of risk for RAS in patients with genetic predisposition is limited due to the rarity of this event, and the bias in referral to the clinic toward younger age. With these limitations the rate of RAS is 0.43xa0% (2/470, 95xa0% CI −0.17 to 1.02, SExa0=xa00.3) in this group in a median follow-up of 8.2xa0years (range 1xa0month to 51xa0years). If we assume irradiation for the breast in 80xa0% of the patients than rate of RAS in group is proximately 0.53xa0% (2/376, 95xa0% CI −0.21 to 1.26, SExa0=xa00.37). A BRCA1 carrier which had sarcoma after irradiation to head and neck carcinoma was not included in these analyses. In conclusion, we found a high frequency of BRCA1/2 mutation among our patients diagnosed with RAS. However, we estimated approximately twofold increase in the risk of RAS in BRCA1/2 carriers which was not significant compared to reports in general population. Therefore, RAS is a rare event in BRCA carriers as in the general population, and should not be considered in the decision regarding irradiation treatment in this population.

Response to neo-adjuvant chemotherapy in BRCA1 and BRCA2 related stage III breast cancer

Pathological features and consequently, tumor response differ between BRCA1/2 carriers and sporadic breast cancer (BC) cases. It is expected that BRCA1/2 associated tumors will be more vulnerable to DNA damaging agents and irradiation due to their function in DNA repair. In addition, very high pathological complete response (pCR) rate of approximately 40–50% to neo-adjuvant chemotherapy were reported by two studies. We describe the clinical outcome, i.e.; complete response (cCR), major pathological response (more than 80% reduction in tumor mass), pathologiacl CR (pCR) and local control rates in 15 BRCA1 and 7 BRCA2 carriers, all diagnosed at stage III and treated with anthracyclin based chemotherapy, mastectomy, and irradiation. cCR were found in 6/15 carriers and in 1/7 BRCA2 carriers (Pxa0=xa00.3). Rate of major pathological response were 4/15 (26.6%) in BRCA1 compared with none of BRCA2 carriers (Pxa0=xa00.3). Of them, pCR was recorded in 2/15 of BRCA1 carriers. Clinical and pathological nodal involvements were lower in BRCA1 carriers. While all BRCA2 carriers remained node positive as compared to 50% of BRCA1 carriers (Pxa0=xa00.047), overall survival was similar in both groups. However, approximately 1/3 of BRCA1 carriers did not respond to chemotherapy and 4/15 died within 5xa0years of diagnosis. We found a non-significant higher clinical and pathological response rate among BRCA1 carriers in response to neo-adjuvant chemotherapy compared with BRCA2 carriers. Our results suggest chemoresistance of approximately a 1/3 of BRCA1 associated tumors. Tumors of BRCA2 carriers are resistant to chemotherapy, while the estrogen receptor positive nature of tumors results in better post recurrence survival.

Absence of founder BRCA1 and BRCA2 mutations in coetaneous malignant melanoma patients of Ashkenazi origin

Introduction Several epidemiologic studies have provided suggestive evidence of a link between coetaneous malignant melanoma (CMM) and breast cancer. The Breast Cancer Linkage Consortium (BCLC) reported approximately 2.6-fold increase in the risk for CMM among BRCA2 carrier families. Methods To evaluate the role of BRCA1/2 mutations in CMM, we screened 92 Jewish patients of Ashkenazi origin diagnosed with CMM for the three Ashkenazi founder mutations: 185delAG and 5382insC in the BRCA1 and 6174delT in the BRCA2 gene. Information about personal demography, family history of cancer, and occupational and lifestyle history was collected. Results Thirty-seven of 92 (40.2%) CMM patients reported a family history of cancer in a first-degree relative. In 14 patients, history of breast cancer (BC) was recorded; however, no family had features associated with BRCA carrier status (i.e., young age at BC onset, history of several BC cases or ovarian cancer in the family). None of the patients were found to carry any of these three mutations. Conclusion Our results suggest a limited role for the three Ashkenazi BRCA founder mutations in CMM risk among the Ashkenazi Jewish population. Therefore, screening patients with CMM for these BRCA1/2 mutations is not warranted.