Triple-negative breast cancer: distinguishing between basal and nonbasal subtypes

PURPOSE

Triple-negative (TN; estrogen receptor, progesterone receptor, and HER-2 negative) cancer and basal-like breast cancer (BLBC) are associated with poor outcome and lack the benefit of targeted therapy. It is widely perceived that BLBC and TN tumors are synonymous and BLBC can be defined using a TN definition without the need for the expression of basal markers.

EXPERIMENTAL DESIGN

We have used two well-defined cohorts of breast cancers with a large panel of biomarkers, BRCA1 mutation status, and follow-up data to compare the clinicopathologic and immunohistochemical features of TN tumors expressing one or more of the specific basal markers (CK5/6, CK17, CK14, and epidermal growth factor receptor; BLBC) with those TN tumors that express none of these markers (TN3BKE-).

RESULTS

Here, we show that although the morphologic features of BLBC are not significantly different from that of TN3BKE- tumors, BLBC showed distinct clinical and immunophenotypic differences. BLBC showed a statistically significant association with the expression of the hypoxia-associated factor (CA9), neuroendocrine markers, and other markers of poor prognosis such as p53. A difference in the expression of cell cycle-associated proteins and biomarkers involved in the immunologic portrait of tumors was seen. Compared with TN3BKE- tumors, BLBC was positively associated with BRCA1 mutation status and showed a unique pattern of distant metastasis, better response to chemotherapy, and shorter survival.

CONCLUSION

TN breast cancers encompass a remarkably heterogeneous group of tumors. Expression of basal markers identifies a biologically and clinically distinct subgroup of TN tumors, justifying the use of basal markers (in TN tumors) to define BLBC.

Use of immunohistochemical markers can refine prognosis in triple negative breast cancer

Background

Basal-like breast cancer has been extensively characterized on the basis of gene expression profiles, but it is becoming increasingly common for these tumors to be defined on the basis of immunohistochemical (IHC) staining patterns, particularly in retrospective studies where material for expression profiling may not be available. The IHC pattern that best defines basal-like tumors is under investigation and various combinations of ER, PR, HER2-, CK5/6+ and EGFR+ have been tested.

Methods

Using datasets from two different hospitals we describe how using different combinations of immunohistochemical patterns has different effects on estimating prognosis at different time intervals after diagnosis. As our baseline, we used two IHC patterns ER-/PR-/HER2-("triple negative phenotype", TNP) and ER-/HER2-/CK5/6+ and/or EGFR+ ("core basal phenotype", CBP).

Results

There was no overall difference in survival between the two hospital-based series, but there was a difference between the TNP and non-TNP groups which was most marked at 3 years (76.8% vs 93.5%, p < .0001). This difference reduced with time, suggesting that long term survivors (beyond 10 years) in the TNP group may have comparable survival to non-TNP cases. A similar difference was seen if CBP was used instead of TNP. However when CK5/6 and/or EGFR expressing tumors were analyzed without consideration of ER/PR status, the reduction in survival increased with time, becoming more pronounced at 10 years than at 3 years.

Conclusion

Our findings suggests that CK5/6 and/or EGFR expressing tumor types have a persistently poorer prognosis over the longer term, an observation that may have important therapeutic implications as drugs that target the EGFR are currently being evaluated in breast cancer.

Effects of food and formulation on the relative bioavailability of bismuth biskalcitrate, metronidazole, and tetracycline given for Helicobacter pylori eradication

AIMS

To evaluate the effects of food and formulation on the pharmacokinetics of bismuth biskalcitrate, metronidazole and tetracycline when combined in a new 3-in-1 single capsule (BMT) for eradication of Helicobacter pylori.

METHODS

In a randomized, 3 x 3 cross-over design, 23 healthy males received one dose of BMT in the fed and fasting states and equivalent doses of the three drugs given together but as separate capsules while fasting. Bioequivalence was evaluated according to 90% confidence intervals (CIs) of ratios of geometric least square means for C(max), AUC(t), and AUC(infinity).

RESULTS

With respect to food, none of the three drugs met bioequivalence guidelines. Bismuth had lower limit CIs ranging from 12% for C(max) to 25% for AUC(infinity). The corresponding values for tetracycline were 59% and 51%. Metronidazole had a lower limit CI of 74% for C(max). With respect to formulation, bismuth had lower limits of CIs ranging from 39% for C(max) to 50% for AUC(t) and higher limits of 146% for AUC(t), metronidazole met bioequivalence guidelines, and tetracycline had lower limits of CIs between 72% for AUC(t) and 74% for AUC(infinity).

CONCLUSIONS

Food significantly decreased the relative bioavailability of each drug but formulation was without effect. This decrease may be beneficial when a local gastric action is needed, as confirmed by a near 90% eradication rate when this combined capsule is administered with food to treat gastro-duodenal local infection by H. pylori.

Placental Cadherin and the Basal Epithelial Phenotype of BRCA1-Related Breast Cancer

PURPOSE

BRCA1-related breast cancer frequently has a basal epithelial phenotype, and P-cadherin is a basal marker. We undertook a detailed evaluation of the relationship among P-cadherin, prognostic markers in breast cancer, and outcome.

EXPERIMENTAL DESIGN

This study was restricted to 292 cases of first primary invasive breast cancer diagnosed in Ashkenazi Jewish women between 1980 and 1995. All available blocks were stained for P-cadherin, and 261 were included in the final statistical analyses, including 27 germ line BRCA1 mutation carriers and 8 BRCA2 mutation carriers. Descriptive analyses were done followed by survival analyses and a Poisson regression analysis.

RESULTS

P-cadherin was present in 80 of the 261 breast cancers (31%) and was more frequently present in tumors that have a basal epithelial phenotype [i.e., high-grade, estrogen receptor- and KIP1 (p27(Kip1))-negative tumors, with expression of cytokeratin 5/6, cyclin E, TP53, and presence of BRCA1 mutations and vascular nests (all P < 0.001)]. In a univariate survival model, expression of P-cadherin was associated with a relative risk (RR) of death from breast cancer at a 10-year follow-up of 2.9 (95% confidence interval, 1.8-4.7; P < 0.0001) and was a predictor of poor univariate survival in both lymph node-negative and -positive breast cancers. In a multivariate analysis, the effect of P-cadherin levels was not independent of other basal-related markers. Multivariable interaction modeling showed that P-cadherin positivity was highly predictive of a poor prognosis in small, node-negative breast cancers (RR, 7.1; P = 0.006).

CONCLUSIONS

P-cadherin is a marker for basal-like breast cancers and is strongly associated with the presence of a BRCA1 mutation. It is an adverse prognostic factor, particularly in small, node-negative breast cancers.

The prognostic implication of the basal-like (cyclin E high/p27 low/p53+/glomeruloid-microvascular-proliferation+) phenotype of BRCA1-related breast cancer

Previous studies have shown that BRCA1-related breast cancers are often high-grade tumors that do not express estrogen receptors, HER2, p27(Kip1), or cyclin D1, but do express p53 and cyclin E. In addition, the expression of cytokeratin 5/6 (CK5/6), indicating a basal epithelial phenotype, is frequent in BRCA1-related breast cancer. Here, in a series of 247 breast cancers, we demonstrate that CK5/6 expression was associated with nearly all of the features of BRCA1-related breast cancer and was also associated with a poor prognosis. In a parsimonious multivariable proportional hazards model, protein levels of cyclin E, p27(Kip1), p53, and the presence of glomeruloid microvascular proliferation all independently predicted outcome after breast cancer. In this model, only cyclin E and p27(Kip1) levels were independent predictors in lymph node-negative cancers, whereas glomeruloid microvascular proliferation and tumor size independently predicted outcome in node-positive disease. The molecular determinants of the basal epithelial phenotype encapsulate many of the key features of breast cancers occurring in germ-line BRCA1 mutation carriers and have independent prognostic value. Basal breast cancer deserves recognition as an important subtype of breast cancer.

Disruption of the expected positive correlation between breast tumor size and lymph node status inBRCA1-related breast carcinoma

BACKGROUND

A positive correlation between breast tumor size and the number of axillary lymph nodes containing tumor is well established. It has been reported that patients with BRCA1-related breast carcinoma are more likely than patients with nonhereditary breast carcinoma to have negative lymph node status. Therefore, the authors questioned whether the known positive correlation between tumor size and lymph node status also was present in women with BRCA1-related breast carcinomas.

METHODS

The relation between the greatest dimension of the resected breast tumor (size) and the presence of positive axillary lymph nodes (expressed as a percentage of all lymph nodes examined) was evaluated in 1555 women with invasive breast carcinoma who were ascertained at 10 centers in North America between 1975 and 1997. There were 276 BRCA1 mutation carriers, 136 BRCA2 carriers, and 1143 women without a known mutation (208 BRCA1/BRCA2 noncarriers and 935 untested women). Patients were stratified according to tumor size, and odds ratios were estimated for the presence of positive lymph nodes with increasing tumor size.

RESULTS

A highly significant positive correlation between tumor size and the frequency of positive axillary lymph nodes was seen for BRCA1/BRCA2 noncarriers, for BRCA2 carriers, and for untested women (overall P < 0.0001 for each). In contrast, there was no clear correlation between tumor size and positive lymph node status in BRCA1 carriers (overall P = 0.20).

CONCLUSIONS

The relation between tumor size and lymph node status in patients with breast carcinoma appears to be different in BRCA1 carriers compared with BRCA2 carriers and noncarriers. These findings have important implications for estimating the route of metastatic spread and for evaluating the effectiveness of early diagnosis in patients with BRCA1-related breast carcinoma.

Impact of germline BRCA1 mutations and overexpression of p53 on prognosis and response to treatment following breast carcinoma: 10-year follow up data

BACKGROUND

Overexpression of p53 has been associated with poor survival following breast carcinoma. BRCA1 interacts biochemically with p53 and may also contribute to poor outcome when constitutionally mutated. The joint effect of both abnormalities has not been studied. The primary objective of this study was to assess the impact of germline BRCA1 mutations and p53 overexpression on survival after 10 years of follow-up.

METHODS

A historical cohort of Ashkenazi Jewish women 65 years or younger with invasive breast carcinoma was tested for BRCA1 founder mutations. p53 overexpression was assessed by immunohistochemistry. Clinicopathologic information was obtained by chart review.

RESULTS

In total, 278 women were analyzed. On univariate analysis, p53 overexpression (n = 63) was prognostic for worse overall survival (relative risk [RR] 2.6, P = 0.001) whereas BRCA1 germline mutations (n = 30) were of borderline significance (RR 1.9, P = 0.052). In the lymph node-negative subpopulation, BRCA1 mutation status conferred a higher mortality on univariate (RR 5.6, P < 0.001) and multivariate (RR 3.5, P = 0.03) analyses. There was a trend in favor of a worse prognosis for women who carried a germline BRCA1 mutation and whose tumor overexpressed p53. When compared with noncarriers, BRCA1 mutation carriers had a worse overall survival if they did not receive adjuvant chemotherapy (RR 3.3, P= 0.01) or adjuvant hormonal therapy (RR 2.3, P = 0.02).

CONCLUSIONS

Germline BRCA1 mutations and p53 overexpression carry a negative prognosis that is not additive to known prognostic factors. Given the experimental sensitivity of BRCA1-mutated cells to chemotherapy, the worse survival among BRCA1 mutation-carrying lymph node-negative breast carcinoma patients may be partly explained by the significantly lower proportion of lymph node-negative patients who received adjuvant chemotherapy (P < 0.001).

Modification of BRCA1- and BRCA2-associated breast cancer risk by AIB1 genotype and reproductive history

Women who have inherited a germ-line mutation in the BRCA1 or BRCA2 (BRCA1/2) genes have a greatly increased risk of developing breast cancer compared with the general population. However, there is also substantial interindividual variability in the occurrence of breast cancer among BRCA1/2 mutation carriers. We hypothesize that genes involved in endocrine signaling may modify the BRCA1/2-associated age-specific breast cancer penetrance. We studied the effect of alleles at the AIB1 gene using a matched case-control sample of 448 women with germ-line BRCA1/2 mutations. We found that these women were at significantly higher breast cancer risk if they carried alleles with at least 28 or 29 polyglutamine repeats at AIB1, compared with women who carried alleles with fewer polyglutamine repeats [odds ratio (OR), 1.59; 95% confidence interval (CI), 1.03-2.47 and OR, 2.85; 95% CI, 1.64-4.96, respectively]. Late age at first live birth and nulliparity have been associated with increased breast cancer risk. We observed increases in BRCA1/2-associated breast cancer risk in women who were either nulliparous or had their first live birth after age 30 (OR, 3.06; 95% CI, 1.52-6.16). Women were at significantly increased risk if they were nulliparous or had a late age at first live birth and had AIB1 alleles no shorter than 28 or 29 or more AIB1 polyglutamine repeats (OR, 4.62; 95% CI, 2.02-10.56 and OR, 6.97; 95% CI, 1.71-28.43, respectively) than women with none of these risk factors. Our results support the hypothesis that pathways involving endocrine signaling, as measured through AIB1 genotype and reproductive history, may have a substantial effect on BRCA1/2-associated breast cancer risk.

Germline BRCA1/2 mutations and p27(Kip1) protein levels independently predict outcome after breast cancer

PURPOSE

Decreased levels of the cyclin-dependent kinase inhibitor p27(Kip1) in breast cancer are associated with a poor outcome. The prognostic significance of BRCA1/2 mutations is less clear, and the relationship between BRCA1/2 mutation status, p27(Kip1) protein levels, and outcome has not been studied.

PATIENTS AND METHODS

Pathology blocks from 202 consecutive Ashkenazi Jewish women with primary invasive breast cancer were studied. Tumor DNA was tested for the three common BRCA1/2 founder mutations present in Ashkenazi Jews, and p27(Kip1) expression was evaluated by immunohistochemistry. The median follow-up was 6.4 years.

RESULTS

Thirty-two tumors (16%) were positive for a BRCA1/2 mutation. Low p27(Kip1) expression was seen in 110 tumors (63%) and was significantly associated with BRCA1/2 mutations (odds ratio, 4.0; 95% confidence interval [CI], 1.4 to 11.1; P =.009). BRCA1/2 mutation carriers had a significantly worse 5-year distant disease-free survival (DDFS) compared with women without BRCA1/2 mutations (58% v 82%; P =.003). Similar results were seen for women whose tumors expressed low levels of p27(Kip1), compared with those with high levels (5-year DDFS, 68% v 93%; P<.0001). In a multivariate analysis, both BRCA1/2 mutation and low p27(Kip1) expression were associated with a shorter DDFS (relative risk [RR], 2.1; 95% CI, 1.0 to 4.3; P =.05; and RR, 3.9; 95% CI, 1.4 to 11.1; P =.01, respectively).

CONCLUSION

In this study, we showed that BRCA1/2 mutations were associated with low levels of p27(Kip1) in breast cancer. Both BRCA1/2 and p27(Kip1) status were identified as independent prognostic factors.

Tamoxifen and risk of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers: a case-control study. Hereditary Breast Cancer Clinical Study Group

BACKGROUND

Women with a mutation in BRCA1 or BRCA2 have a high risk of developing breast cancer and of contralateral cancer after the initial diagnosis of breast cancer. Tamoxifen protects against contralateral breast cancer in the general population, but whether it protects against contralateral breast cancer in BRCA1 or BRCA2 mutation carriers is not known.

METHODS

We compared 209 women with bilateral breast cancer and BRCA1 or BRCA2 mutation (bilateral-disease cases), with 384 women with unilateral disease and BRCA1 or BRCA2 mutation (controls) in a matched case-control study. Age and age at diagnosis of breast cancer (range 24-74 years) were much the same in bilateral-disease cases and controls, and both groups had been followed up for the same time for a second primary breast cancer. History of tamoxifen use for first breast cancer was obtained by interview, or by self-administered questionnaire.

FINDINGS

The multivariate odds ratio for contralateral breast cancer associated with tamoxifen use was 0.50 (95% CI 0.28-0.89). Tamoxifen protected against contralateral breast cancer for carriers of BRCA1 mutations (odds ratio 0.38, 95% CI 0.19-0.74) and for those with BRCA2 mutations (0.63, 0.20-1.50). In women who used tamoxifen for 2-4 years, the risk of contralateral breast cancer was reduced by 75%. A reduction in risk of contralateral cancer was also seen with oophorectomy (0.42, 0.22-0.83) and with chemotherapy (0-40, 0.26-0.60).

INTERPRETATION

Tamoxifen use reduces the risk of contralateral breast cancer in women with pathogenic mutations in the BRCA1 or BRCA2 gene. The protective effect of tamoxifen seems independent of that of oophorectomy.

BRCA1 and BRCA2 mutation analysis of 208 Ashkenazi Jewish women with ovarian cancer

Ovarian cancer is a component of the autosomal-dominant hereditary breast-ovarian cancer syndrome and may be due to a mutation in either the BRCA1 or BRCA2 genes. Two mutations in BRCA1 (185delAG and 5382insC) and one mutation in BRCA2 (6174delT) are common in the Ashkenazi Jewish population. One of these three mutations is present in approximately 2% of the Jewish population. Each mutation is associated with an increased risk of ovarian cancer, and it is expected that a significant proportion of Jewish women with ovarian cancer will carry one of these mutations. To estimate the proportion of ovarian cancers attributable to founding mutations in BRCA1 and BRCA2 in the Jewish population and the familial cancer risks associated with each, we interviewed 213 Jewish women with ovarian cancer at 11 medical centers in North America and Israel and offered these women genetic testing for the three founder mutations. To establish the presence of nonfounder mutations in this population, we also completed the protein-truncation test on exon 11 of BRCA1 and exons 10 and 11 of BRCA2. We obtained a detailed family history on all women we studied who had cancer and on a control population of 386 Ashkenazi Jewish women without ovarian or breast cancer. A founder mutation was present in 41.3% of the women we studied. The cumulative incidence of ovarian cancer to age 75 years was found to be 6.3% for female first-degree relatives of the patients with ovarian cancer, compared with 2.0% for the female relatives of healthy controls (relative risk 3.2; 95% CI 1.5-6.8; P=.002). The relative risk to age 75 years for breast cancer among the female first-degree relatives was 2.0 (95% CI 1.4-3.0; P=.0001). Only one nonfounder mutation was identified (in this instance, in a woman of mixed ancestry), and the three founding mutations accounted for most of the observed excess risk of ovarian and breast cancer in relatives.

Primary node negative breast cancer in BRCA1 mutation carriers has a poor outcome

BACKGROUND

The association between BRCA1 germ-line mutations and breast cancer prognosis is controversial. A historical cohort study was designed to determine the prognosis for women with axillary lymph node negative hereditary breast cancer.

PATIENTS AND METHODS

We tested pathology blocks from 118 Ashkenazi Jewish women with axillary lymph node negative breast cancer for the presence of the two common BRCA1 founder mutations, 185delAG and 5382insC. Patients were followed up for a median of 76 months. Somatic TP53 mutations were screened for by immunohistochemistry, and direct sequencing was performed in the BRCA1-positive tumours.

RESULTS

Sixteen breast cancer blocks (13.6%) carried a BRCA1 mutation. Young age of onset, high nuclear grade, negative estrogen receptor status and over-expression of p53 were highly associated with BRCA1-positive status (P-values all <0.01). BRCA1 mutation carriers had a higher mortality than non-carriers (five-year overall survival, 50% and 89.6%, respectively, P = 0.0001). Young age of onset, estrogen receptor negative status, nuclear grade 3, and over-expression of p53 also predicted a poor outcome. Cox multivariate analyses showed that only germ-line BRCA1 mutation status was an independent prognostic factor for overall survival (P = 0.01). Among nuclear grade 3 tumours, the BRCA1 mutation carrier status was a significant prognostic factor of death (risk ratio 5.8, 95% confidence interval: 1.5-22, P = 0.009). Sequencing of BRCA1-related breast cancers revealed one TP53 missense mutation not previously reported in breast cancer.

CONCLUSIONS

Using a historical cohort approach, we have identified BRCA1 mutation status as an independent prognostic factor for node negative breast cancer among the Ashkenazi Jewish women. Those managing women carrying a BRCA1 mutation may need take these findings into consideration. Additionally, our preliminary results, taken together with the work of others suggest a different carcinogenic pathway in BRCA1-related breast cancer, compared to non-hereditary cases.

Pregnancy and risk of early breast cancer in carriers of BRCA1 and BRCA2

BACKGROUND

Early age at first full-term pregnancy and increasing parity are associated with a reduced risk of breast cancer. However, whether pregnancy decreases the risk of early-onset hereditary breast cancer is unknown. There is concern that pregnancy may increase breast-cancer risk in carriers of BRCA1 and BRCA2 germline mutations. We aimed to establish whether pregnancy is a risk factor for hereditary breast cancer.

METHODS

We did a matched case-control study of breast cancer in women who carry deleterious BRCA1 or BRCA2 mutations. Cases were carriers who developed breast cancer by age 40 years, and controls were carriers of the same age without breast cancer, or who were diagnosed with breast cancer after age 40 years. Women who had undergone preventive mastectomy, hysterectomy, or oophorectomy, or who were diagnosed with ovarian cancer before the age at which breast cancer was diagnosed in the matched case were excluded. Information about pregnancies and pregnancy outcome was derived from a questionnaire completed by women in the course of genetic counselling.

FINDINGS

A higher proportion of cases than controls had had a full term pregnancy (173/236 vs 146/236; odds ratio 1.71 [95% CI 1.13-2.62], p=0.01). The mean number of births was also greater for cases than for controls (1.62 vs 1.38, p=0.04). The risk increased with the number of births and did not diminish with time since last pregnancy. There were no significant differences in age at first birth or age at last birth between cases and controls.

INTERPRETATION

Carriers of the BRCA1 and BRCA2 mutations who have children are significantly more likely to develop breast cancer by age 40 than carriers who are nulliparous. Each pregnancy is associated with an increased cancer risk. An early first pregnancy does not confer protection for carriers of BRCA1 or BRCA2 mutations.

The effect of the I1307K APC polymorphism on the clinicopathological features and natural history of breast cancer

The I1307K polymorphism in APC has been found to predispose to colorectal cancer in Ashkenazi Jews, and has recently been associated with an increased risk for breast cancer in the same population. In that study, we genotyped 205 paraffin-embedded breast cancers from Ashkenazi Jewish women diagnosed below the age of 65. We now present an extended analysis, with clinicopathological correlations between carriers of I1307K and non-carriers. Twenty-four of 209 cases (11.5%, 95% confidence interval 7.5-16.6) were found to carry the I1307K polymorphism. When stratifying the data by other relevant clinicopathological variables, we observed no association between the presence of this polymorphism and age at diagnosis (P = 0.52), grade (P = 0.074), tumour size (P = 0.99), lymph node status (P = 0.82), oestrogen receptor status (P = 0.23) or P53 immunoreactivity (P = 0.80). The breast-cancer specific 5-year survival for women with I1307 K polymorphism was 88.9% compared with 81.6% in women without I1307K (P = 0.34). Using microdissected samples and direct sequencing, no somatic mutations were observed in any of the 24 I1307K-positive cases. Single-strand conformation analysis of 158 of the I1307K-negative breast cancers that were available for study revealed no mobility shifts. We conclude that the presence of the I1307K polymorphism does not appear to be associated with any particular clinicopathological feature of breast cancer and importantly, does not affect the prognosis.

Intron variants of the p53 gene are associated with increased risk for ovarian cancer but not in carriers of BRCA1 or BRCA2 germline mutations

Two biallelic polymorphisms in introns 3 and 6 of the p53 gene were analysed for a possible risk-modifying effect for ovarian cancer. Germline DNA was genotyped from 310 German Caucasian ovarian cancer patients and 364 healthy controls. We also typed 124 affected and 276 unaffected female carriers with known deleterious BRCA1 or BRCA2 germline mutation from high-risk breast-ovarian cancer families. Genotyping was based on PCR and high-resolution gel electrophoresis. German ovarian cancer patients who carried the rare allele of the MspI restriction fragment length polymorphism (RELP) in intron 6 were found to have an overall 1.93-fold increased risk (95% confidence internal (CI) 1.27-2.91) which further increased with the age at diagnosis of 41-60 years (odds ratio (OR) 2.71, 95% CI 1.10-6.71 for 41-50 and OR 2.44, 95% CI 1.12-5.28 for 51-60). The 16 bp duplication polymorphism in intron 3 was in a strong linkage to the MspI RFLP. In BRCA1 or BRCA2 mutation carriers, no difference in allele frequency was observed for carriers affected or unaffected with ovarian cancer. Our data suggest that intronic polymorphisms of the p53 gene modify the risk for ovarian cancer patients but not in carriers with BRCA1 or BRCA2 mutations.

Prevalence and penetrance of BRCA1 and BRCA2 gene mutations in unselected Ashkenazi Jewish women with breast cancer

BACKGROUND

Approximately 2.0%-2.5% of Ashkenazi Jewish women carry one of three founding mutations in the BRCA1 and BRCA2 genes, and each mutation is associated with a high lifetime risk of invasive breast cancer. We investigated the extent to which these three mutations contribute to breast cancer incidence in the Ashkenazi Jewish population.

METHODS

We ascertained 457 Jewish women with prevalent cases of breast cancer who were unselected for age or family history of the disease; 412 of these women were tested for the three founder mutations (case patients). Control subjects consisted of 360 non-Jewish women with breast cancer (control patients) and 380 healthy Jewish women with no history of cancer (control subjects).

RESULTS

Mutations were found in 48 (11.7%) of 412 Jewish case patients. Forty-six of 48 mutations occurred in women with early-onset breast cancer (<50 years) or a history of ovarian or early-onset breast cancer in a first-, second-, or third-degree relative. The estimated penetrance to age 70 years for breast cancer was 59.9% for the BRCA1 gene mutations and 28.3% for the BRCA2 gene mutation. Compared with Jewish control subjects, the relative risk (RR) of breast cancer for first-degree relatives of mutation carriers was 5.16 (95% confidence interval [CI] = 3.14-8. 48), but risk was also increased for relatives of noncarriers (RR = 1.66; 95% CI = 1.18-2.33). The RR of prostate cancer for first-degree relatives of Jewish case patients was 3.36 (95% CI = 1. 49-7.56).

CONCLUSIONS

Approximately 12% of breast cancers in the Ashkenazi Jewish population are attributable to mutations in the BRCA1 or BRCA2 gene. Genetic testing may be useful when Jewish women with breast cancer are diagnosed before age 50 years or have a close relative with ovarian or early-onset breast cancer. An association between breast and prostate cancers was observed in our study population.

Genetic implications of double primary cancers of the colorectum and endometrium

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant condition predisposing to cancers of the colorectum and endometrium. Endometrial cancer is the most commonly occurring extracolonic cancer in HNPCC. Estimates of the cumulative incidence of endometrial cancer in women with mutations in the HNPCC genes range from 22-43%. In order to determine how frequently double primary cancers of the colorectum and endometrium are the result of a hereditary factor, we conducted a registry based study in Ontario and Quebec, Canada. We obtained pedigrees on 80 women diagnosed with double primary cancers of the colorectum and endometrium at less than 70 years of age. Family histories of cancer were obtained for all first degree relatives of these women and cancer rates were compared with age standardised provincial incidence rates in order to estimate the relative risks. There was a total of 82 cancers observed in relatives below the age of 55, compared with 31.2 expected, giving a relative risk of 2.6 (95% confidence interval (CI) 2.1-3.3). The relative risk for colorectal cancer below 55 was 16.1 (95% CI 11.6-21.8). This risk decreased with increasing age of onset of cancers in probands. For probands with both colorectal and endometrial cancer diagnosed under the age of 55, the relative risk of colorectal cancer in relatives below the age of 55 was 30.5 (95% CI 18.8-46.6). Similar patterns were observed for endometrial and pancreatic cancer. There were non-significant increases in rates of cancer of the oesophagus, stomach, small intestine, and bladder. There was no increased risk of breast cancer. The risk of lung cancer was decreased, especially in older relatives. Our findings indicate the presence of a significant genetic component of cancer in women with double primary cancers of the colorectum and endometrium.

Oral contraceptives and the risk of hereditary ovarian cancer. Hereditary Ovarian Cancer Clinical Study Group

BACKGROUND

Women with mutations in either the BRCA1 or the BRCA2 gene have a high lifetime risk of ovarian cancer. Oral contraceptives protect against ovarian cancer in general, but it is not known whether they also protect against hereditary forms of ovarian cancer.

METHODS

We enrolled 207 women with hereditary ovarian cancer and 161 of their sisters as controls in a case-control study. All the patients carried a pathogenic mutation in either BRCA1 (179 women) or BRCA2 (28 women). The control women were enrolled regardless of whether or not they had either mutation. Lifetime histories of oral-contraceptive use were obtained by interview or by written questionnaire and were compared between patients and control women, after adjustment for year of birth and parity.

RESULTS

The adjusted odds ratio for ovarian cancer associated with any past use of oral contraceptives was 0.5 (95 percent confidence interval, 0.3 to 0.8). The risk decreased with increasing duration of use (P for trend, <0.001); use for six or more years was associated with a 60 percent reduction in risk. Oral-contraceptive use protected against ovarian cancer both for carriers of the BRCA1 mutation (odds ratio, 0.5; 95 percent confidence interval, 0.3 to 0.9) and for carriers of the BRCA2 mutation (odds ratio, 0.4; 95 percent confidence interval, 0.2 to 1.1).

CONCLUSIONS

Oral-contraceptive use may reduce the risk of ovarian cancer in women with pathogenic mutations in the BRCA1 or BRCA2 gene.

Risk factors for familial and sporadic ovarian cancer among French Canadians: a case-control study

OBJECTIVE

The objective was to compare risk factors between familial and sporadic ovarian cancer by means of a case-control approach.

STUDY DESIGN

We conducted a case-control study among French Canadian women in Montreal during 1995-1996. One hundred seventy women 20 to 84 years old with histologically confirmed diagnoses of primary ovarian carcinomas or borderline tumors were interviewed concerning their reproductive, family, and medical histories. During the same period 170 randomly selected population control subjects, frequency-matched to the case patients according to age and ethnic group, were also interviewed. Unconditional logistic regression methods were used for data analysis.

RESULTS

The major factors influencing the risk of development of ovarian cancer were as follows: (1) family history of breast or ovarian cancer, (2) a late age at use of oral contraceptives (a protective effect), and (3) a late age at last childbirth (a protective effect for familial case patients only).

CONCLUSION

These factors had equally great impacts in familial and sporadic cases, implying that the underlying mechanisms of carcinogenesis in sporadic and familial ovarian cancer may be similar and that hereditary ovarian cancer may be preventable.

No association of the I1307K APC allele with ovarian cancer risk in Ashkenazi Jews

Familial adenomatous polyposis is a dominantly inherited colon cancer syndrome associated with germ-line mutations in the APC tumor suppressor gene. An APC gene sequence alteration, the I1307K allele, occurs in 6% of the Ashkenazi Jewish population and is reported to double the risk for colorectal cancer. We screened a population of 190 Ashkenazi women who were diagnosed with epithelial ovarian carcinoma for the I1307K variant and measured the effect of this allele on the risk for cancer development in their first-degree relatives. We identified the I1307K allele in 7.9% (15 of 190) of our ovarian cancer cases. The average age of ovarian cancer diagnosis in carriers of the I1307K allele (57.5 years) was not statistically different than the age for noncarriers (56.4 years; P = 0.70). Among the 1087 first-degree relatives, there were 23 cases of colorectal cancer; 3 of 100 relatives of probands with the I1307K allele (3.0%) had a history of colorectal cancer versus 20 of 987 relatives of probands without the I1307K allele (2.1%; relative risk, 1.48; 95% confidence interval, 0.45-4.88; P = 0.462). Relatives of the I1307K carriers had a risk of 38.0% for developing any cancer to age 80, similar to the risk for relatives of noncarriers of the I1307K allele (42.1%; P = 0.86). The average age of diagnosis of cancer of any type was not different between relatives of carriers (59.0 years) and noncarriers (60.4 years). In the Ashkenazi Jewish population, the I1307K allele is unlikely to increase the risk of ovarian cancer or of cancer in general.

Effect of smoking on breast cancer in carriers of mutant BRCA1 or BRCA2 genes

BACKGROUND

Smoking has carcinogenic effects, and possibly antiestrogenic effects as well, but it has not been found to be a risk factor for breast cancer in women in the general population. However, hereditary breast cancer is primarily a disease of premenopausal women, and interactions between genes and hormonal and environmental risk factors may be particularly important in this subgroup.

METHODS

We conducted a matched case-control study of breast cancer among women who have been identified to be carriers of a deleterious mutation in either the BRCA1 or the BRCA2 gene. These women were assessed for genetic risk at one of several genetic counseling programs for cancer in North America. Information about lifetime smoking history was derived from a questionnaire routinely administered to women who were found to carry a mutation in either gene. Smoking histories of case subjects with breast cancer and age-matched healthy control subjects were compared. Odds ratios for developing breast cancer were determined for smokers versus nonsmokers by use of conditional logistic regression for matched sets after adjustment for other known risk factors.

RESULTS

Subjects with BRCA1 or BRCA2 gene mutations and breast cancer were significantly more likely to have been nonsmokers than were subjects with mutations and without breast cancer (two-sided P = .007). In a multivariate analysis, subjects with BRCA1 or BRCA2 mutations who had smoked cigarettes for more than 4 pack-years (i.e., number of packs per day multiplied by the number of years of smoking) were found to have a lower breast cancer risk (odds ratio = 0.46, 95% confidence interval = 0.27-0.80; two-sided P = .006) than subjects with mutations who never smoked.

CONCLUSIONS

This study raises the possibility that smoking reduces the risk of breast cancer in carriers of BRCA1 or BRCA2 gene mutations.

Germ-line BRCA1 mutation is an adverse prognostic factor in Ashkenazi Jewish women with breast cancer

Germ-line mutations in BRCA1 confer an increased risk of developing breast and ovarian cancer, but little is known about the clinical course of breast cancer in BRCA1 mutation carriers compared with noncarriers. Two recurrent BRCA1 mutations (185delAG and 5382insC) are common ( approximately 1.3%) in Ashkenazi Jews and account for about 20% of breast cancers diagnosed before age 40 in this group. We assayed paraffin-embedded tumor blocks from 117 unselected Ashkenazi Jewish women with primary breast cancer, diagnosed before age 65 at a single institution, for the presence of either of the two BRCA1 mutations. We reviewed the medical records and constructed survival curves for BRCA1-positive and -negative subgroups. Twelve of the women (10.3%) were found to carry BRCA1 mutations (eight mutations were 185delAG, and four were 5382insC). The probability of death from breast cancer in the first 5 years was 35.7% in the BRCA1 mutation-positive group and 4.3% in the 100 women without a mutation (P = 0.0023). The 5-year distant disease-free survival was 68.2% in BRCA1 mutation carriers and 88.7% in noncarriers (P = 0.019). These data suggest that breast cancer occurring in an Ashkenazi Jewish woman carrying a germ-line BRCA1 mutation has an adverse prognosis. This information is available before the diagnosis of breast cancer, and therefore, this finding may have important implications for prevention of breast cancer in BRCA1 mutation carriers.

Cutaneous malignant melanoma in women is uncommonly associated with a family history of melanoma in first-degree relatives: a case-control study

Sun exposure is the principal cause of malignant melanoma, but other risk factors may be important. During their reproductive years women are at a greater risk for melanoma than men. We performed an age-matched case-control study of cutaneous malignant melanoma in 159 women attending a single oncology clinic in Montreal. A reported family history of cutaneous malignant melanoma in first-degree relatives was associated with a significantly increased risk of melanoma (adjusted relative risk: 4.28, P = 0.046). No subject was a member of a hereditary melanoma family (three or more cases of melanoma in first-degree relatives). As expected, variables related to sun exposure were also strong determinants of risk. Height was a significant risk factor, but the difference between the mean heights of cases and controls was only 2 cm (P = 0.009). The age of menarche of cases was lower than in controls (mean 12.70 and 13.08 years respectively, P = 0.036) but there was no significant elevation in risk associated with other reproductive variables. This study suggests that a family history of malignant melanoma is a significant risk factor, but that hereditary melanoma may be less common than is currently believed.

Familial risks of squamous cell carcinoma of the head and neck: retrospective case-control study

OBJECTIVE

To determine the contribution of inheritance to the incidence of squamous cell carcinoma of the head and neck.

DESIGN

Historical cohort study. First degree relatives of cases with squamous cell carcinoma of the head and neck made up the exposed cohort and first degree relatives of spouses of cases made up the comparison unexposed cohort.

SETTING

Ear, nose, and throat clinic in a large metropolitan teaching hospital.

SUBJECTS

1429 first degree relatives of 242 index cases of squamous cell carcinoma of the head and neck; as controls, 934 first degree relatives of the spouses of 156 index cases.

MAIN OUTCOME MEASURES

Relative risk of developing squamous cell carcinoma in first degree relatives of cases compared with risk in first degree relatives of spouses.

RESULTS

The adjusted relative risk for developing head and neck cancer if the index case had squamous cell carcinoma of the head and neck was 3.79 (95% confidence interval 1.11 to 13.0). There were no significantly increased risks associated with a family history of cancer at other sites. The adjusted relative risk for squamous cell carcinoma of the head and neck was 7.89 (1.50 to 41.6) in first degree relatives of patients with multiple primary head and neck tumours.

CONCLUSIONS

These data suggest that genetic factors are important in the aetiology of head and neck cancer, in particular for patients with multiple primary cancers. Given the prolonged exposure of these subjects to carcinogens, these genetic factors may have a role in modifying carcinogen activity or in host resistance to carcinogens. Inherited factors may be important in persons with environmentally induced cancers.

Family history of cancer is a risk factor for squamous cell carcinoma of the head and neck in Brazil: a case-control study

To determine the role of familial factors in head and neck cancer, we analysed data from a hospital-based case-control study of squamous cell carcinoma of the head and neck in Brazil. There were 754 cases of squamous cell carcinoma of the head and neck (SCCHN) and 1,507 age- and gender-matched hospital-based controls with non-malignant diseases. Subjects provided information on the occurrence of cancer in first-degree relatives, as well as about other risk factors, including tobacco and alcohol consumption. Relative risks (RRs) were estimated for developing mouth, pharynx and larynx cancer when cancers in relatives were observed. RRs were adjusted for age, sex, city of admission and alcohol and tobacco consumption. The RR for developing SCCHN if a first-degree relative had cancer at any site was significantly elevated at 1.97. The RR was 3.65 (95% CI: 1.97-6.76) if the relative had head and neck cancer. Significantly elevated risks for developing head and neck cancer were associated with siblings with head and neck cancer (RR = 8.57) and, to a lesser extent, with fathers with head and neck cancer (RR = 2.49). There was no significantly increased risk associated with mothers with head and neck cancer, but these tumours were rare among mothers. Our data show that familial, possibly genetic, factors are important in the aetiology of head and neck cancer.