Progesterone receptor variant increases ovarian cancer risk in BRCA1 and BRCA2 mutation carriers who were never exposed to oral contraceptives

Contraception as chemoprevention of ovarian cancer in BRCA1 and BRCA2 women

Ovarian cancer is the seventh most common cancer in women in the world, with an estimated worldwide mortality of over 207'000 women every year. This cancer, due to the current lack of adequate screening techniques, is commonly diagnosed late and has a poor prognosis. The oral contraceptive pill is considered the most effective prevention strategy for ovarian cancer in the general population, being associated with a decreased incidence while also having a substantial positive impact on the mortality rate, which is reduced by up to 50%. BRCA1 and BRCA2 germline mutated women have an augmented risk of ovary and breast cancer: despite international guidelines that consider prophylactic surgery as the gold standard for ovarian cancer prevention, there are currently no effective non-invasive preventive methods. In BRCA1\2 mutated patients, clinicians should weigh the benefits of contraceptive pills against the risk of long-term thromboembolic side effects and hormonal malignancies such as breast and cervical cancer. A multidisciplinary team should counsel patients on the most appropriate risk-reduction strategy tailored to their needs and expectations, proposing the oral contraceptive pill to selected patients after balancing the risks of adverse effects and the benefits on both contraception and chemoprevention.

Progesterone Receptor Gene Polymorphisms and Breast Cancer Risk

The objective of this systematic review was to investigate the association between polymorphisms in the progesterone receptor gene (PGR) and breast cancer risk. A search of PubMed, Scopus, and Web of Science databases was performed in November 2021. Study characteristics, minor allele frequencies, genotype frequencies, and odds ratios were extracted. Forty studies met the eligibility criteria and included 75 032 cases and 89 425 controls. Of the 84 PGR polymorphisms reported, 7 variants were associated with breast cancer risk in at least 1 study. These polymorphisms included an Alu insertion (intron 7) and rs1042838 (Val660Leu), also known as PROGINS. Other variants found to be associated with breast cancer risk included rs3740753 (Ser344Thr), rs10895068 (+331G/A), rs590688 (intron 2), rs1824128 (intron 3), and rs10895054 (intron 6). Increased risk of breast cancer was associated with rs1042838 (Val660Leu) in 2 studies, rs1824128 (intron 3) in 1 study, and rs10895054 (intron 6) in 1 study. The variant rs3740753 (Ser344Thr) was associated with decreased risk of breast cancer in 1 study. Mixed results were reported for rs590688 (intron 2), rs10895068 (+331G/A), and the Alu insertion. In a pooled analysis, the Alu insertion, rs1042838 (Val660Leu), rs3740753 (Ser344Thr), and rs10895068 (+331G/A) were not associated with breast cancer risk. Factors reported to contribute to differences in breast cancer risk associated with PGR polymorphisms included age, ethnicity, obesity, and postmenopausal hormone therapy use. PGR polymorphisms may have a small contribution to breast cancer risk in certain populations, but this is not conclusive with studies finding no association in larger, mixed populations.

Association of the PROGINS PgR polymorphism with susceptibility to female reproductive cancer: A meta-analysis of 30 studies

Aims

The progesterone response of the nuclear progesterone receptor plays an important role in the female reproductive system. Changes in the function of the progesterone receptor gene may increase the risk of reproductive cancer. The present study performed a meta-analysis to examine whether the progesterone receptor gene PROGINS polymorphism was a susceptibility factor for female reproductive cancer.

Materials and methods

We searched the PubMed, Cochrane Library, Web of Science and EMBASE databases for literature on PROGINS polymorphisms and female reproductive cancer published before September 2020. We evaluated the risk using odds ratios [ORs] and 95% confidence intervals via fixed effects models and random-effects models, which were calculated for all five genetic models. We grouped the analyses by race, cancer, and HWE.

Results

Thirty studies comprised of 25405 controls and 19253 female reproductive cancer cases were included in this meta-analysis. We observed that the Alu insertion polymorphism and the V660L polymorphism were significantly associated with female reproductive cancer in the allele and dominant genetic models. The allele genetic model and (Alu-insertion polymorphism: OR = 1.22, 95% CI = 1.02–1.45; V660L polymorphism: OR = 1.02, 95% CI = 1.00–1.13) dominant genetic model (Alu-insertion polymorphism: OR = 1.27, 95% CI = 1.03–1.58; V660L polymorphism: OR = 1.10, 95% CI = 1.011.19) demonstrated a significantly increased risk of female reproductive cancer. A subgroup analysis according to ethnicity found that the Alu insertion was associated with female reproductive cancer incidence in white (Allele model: OR = 1.21, 95% CI = 1.00–1.45; Heterozygous model: OR = 3.44, 95% CI = 1.30–9.09) and Asian (Dominant model: OR = 3.12, 95% CI = 1.25–7.79) populations, but the association disappeared for African and mixed racial groups. However, the V660L polymorphism was significantly associated with female reproductive cancer in the African (Allele model: OR = 2.52, 95% CI = 1.14–5.56; Heterozygous model: OR = 2.83, 95% CI = 1.26–6.35) and mixed racial groups (Dominant model: OR = 1.28, 95% CI = 1.01–1.62). Subgroup analysis by cancer showed that the PROGINS polymorphism increased the risk of cancer in the allele model, dominant mode and heterozygous model, but the confidence interval for this result spanned 1 and was not statistically significant. This sensitivity was verified in studies with HWE greater than 0.5.

Conclusion

Our meta-analysis showed that the progesterone receptor gene Alu insertion and the V660L polymorphism contained in the PROGINS polymorphism were susceptibility factors for female reproductive cancer.

Genetic variation in progesterone receptor gene and ovarian cancer risk: A case control study

BACKGROUND

Previous studies examined the association of genetic variation in progesterone receptor (PR) gene (PGR) with ovarian cancer, possibly by altering the expression of PR-B isoform, but with mixed outcome.

OBJECTIVE

This study evaluated the association of PGR variants with ovarian cancer and associated features.

METHODS

This was a retrospective case-control study, which involved 82 women with ovarian cancer and 95 cancer-free women who served as controls. Genotyping was done by Taqman® SNP genotyping by qRT-PCR. The PGR variants tested were rs471767 (A > G), rs590688 (G > C), and rs10895068 (G > A). Stratification analyses were used for testing the correlation between the PGR variants with ovarian cancer susceptibility according to menstruation status, FIGO classification, pathological grade, and chemotherapy.

RESULTS

Significantly lower minor allele frequency (MAF) of rs10895068 was seen among ovarian cancer patients, thereby imparting disease protective nature to this variant. Significant association of rs10895068 genotypes with ovarian cancer was seen under the dominant model, but not other genetic models. FIGO classification correlated positively with rs471767 and rs10895068, while rs10895068 correlated positively with lymph node positivity. Three-locus haplotype analysis identified ACA and HCG haplotypes to be negatively associated with the risk of ovarian cancer.

CONCLUSIONS

This report confirms the contribution of PGR variants, specifically the rs10895068 (+331G/A) the etiology of ovarian cancer.

Use of oral contraceptives in BRCA mutation carriers and risk for ovarian and breast cancer: a systematic review

PURPOSE

BRCA mutation carriers have an increased risk of developing breast or ovarian cancer. Oral contraception (OC) is known to increase breast cancer and reduce ovarian cancer risk in the general population. This review analyses the published data on OC and risk of cancer in BRCA mutation carriers.

METHODS

We included all relevant articles published in English from 1995 to 2018. Literature was identified through a search on PubMed and Cochrane Library.

RESULTS

We included four meta-analyses, one review, one case-control study and one retrospective cohort study on the association between ovarian cancer and OC in BRCA mutation carriers. All report a risk reduction for the OC users and several also describe an inverse correlation with duration of use. Regarding breast cancer, we included four meta-analyses, one review, one case-control study, two case-only studies, one prospective and one retrospective cohort study. Some studies report a risk elevation, while others did not find an association between OC use and breast cancer in BRCA mutation carriers. In other studies, the association was limited to early-onset breast cancer and/or associated with young age at first start of OC.

CONCLUSION

Oral contraception leads to a risk reduction of ovarian cancer also in BRCA mutation carriers. An increase in breast cancer risk due to OC cannot be excluded. Women with BRCA mutation who consider OC use have to be informed about possible increase in breast cancer risk and alternative contraceptive methods. OC should not be used for the prevention of ovarian cancer in this population.

Mutations in the Progesterone Receptor (PROGINS) May Reduce the Symptoms of Acute Hepatitis E and Protect Against Infection

BACKGROUND

Mutations in the progesterone receptor (PR) gene, PROGINS, have been studied in relation to hepatitis E virus (HEV) infection. Patients with the PROGINS gene may develop a worse clinical course of hepatitis E. The aim of our study was to evaluate the influence of PROGINS on the susceptibility to and the clinical course of HEV infection in HIV patients.

METHODS

This study included patients with HIV who were evaluated in previous prospective studies for the prevalence and incidence of HEV. The following three groups of patients were studied: (i) never infected, (ii) past infections, and (iii) recently infected. We determined the PR genotype to evaluate the proportion of patients who were homozygous for PROGINS according to HEV infection. We also compared the proportion of PROGINS carriers with a recent HEV infection according to their symptomatology.

RESULTS

In this study, 311 patients infected with HIV were included. Of those patients, 198 were homozygous wild type (63.7%), 91 were heterozygous (29.3%), and 22 were homozygous PROGINS (7.1%). We found that the homozygous PROGINS genotype in women was associated with a lower HEV seroprevalence. In addition, in patients with a recent HEV infection, none of those homozygous for PROGINS presented symptoms.

CONCLUSION

The PROGINS mutation plays a protective role against HEV infection and is associated with subclinical infection in HIV-infected patients, particularly women.

Association of the Alu insertion polymorphism in the progesterone receptor gene with breast cancer in a Mexican population

INTRODUCTION

The progesterone receptor (PR) gene plays an important role in reproduction-related events. Data on polymorphisms in the PR gene have revealed associations with cancer, particularly for the Alu insertion polymorphism, which has been suggested to affect progesterone receptor function and contribute to tumor promotion in the mammary gland.

MATERIAL AND METHODS

We examined the role of the Alu insertion polymorphism in the PR gene by comparing the genotypes of 209 healthy Mexican women with those of 481 Mexican women with breast cancer (BC).

RESULTS

The genotype frequencies observed in the controls and BC patients were 0% and 4% for T2/T2 (Alu insertion), 16% and 21% for T1/T2, and 84% and 75% for T1/T1 (Alu deletion), respectively. The obtained odds ratio (OR) was 1.7, with a 95% confidence interval (95% CI) of 1.1-2.6, p = 0.009, for the T1/T2-T2/T2 genotypes. The association was also evident when the distributions of the T1/T2-T2/T2 genotypes in patients in the following categories were compared: obesity grade II (OR = 1.81, 95% CI: 1.03-3.18, p = 0.039) and the chemotherapy response (OR = 1.91, 95% CI: 1.27-3.067, p = 0.002).

CONCLUSIONS

The T1/T2-T2/T2 genotypes of the Alu insertion polymorphism in the PR gene are associated with BC susceptibility in the analyzed Mexican population.

Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry

BACKGROUND

Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry.

METHODS

We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls).

RESULTS

In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only.

CONCLUSION

We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.

Progesterone receptor PROGINS and +331G/A polymorphisms confer susceptibility to ovarian cancer: a meta-analysis based on 17 studies

Progesterone and its receptor, progesterone receptor (PGR), have been widely studied for their roles in the onset and development of ovarian cancer. Although numerous epidemiological studies have focused on the association of PGR PROGINS and +331G/A polymorphisms with ovarian cancer susceptibility, presently, available results remain controversial, in part due to low sample sizes. Thus, a meta-analysis is required to evaluate this association. A literature search of PubMed, Embase, Web of Science, CNKI, and CBM databases was performed to retrieve eligible studies published before August 15, 2013. Summary odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of this association. All analyses were done using STATA 12.0 software (Stata Corp., College Station, TX, USA). Seventeen case-control studies with a total of 6,365 cases and 9,998 controls were identified. While no statistically significant association between the PROGINS allele and ovarian cancer risk was found in an overall analysis, a stratified analysis revealed that for Caucasians, never-oral contraceptive (OC) users, and serous tumor patients, there were statistically significant ORs for ovarian cancer risk associated with the mutated PROGINS allele. No significant association, however, between the +331G/A polymorphism and ovarian cancer susceptibility was observed in the overall analyses and subgroup analyses based on ethnicity and histological type. This meta-analysis provides evidence that the PROGINS allele occurs more frequently in ovarian cancer patients and especially in non-OC users and serous cancer patients, indicating that PROGINS may be a risk modifier. No significant association between the +331G/A polymorphism and ovarian cancer was found, even in stratified analyses by ethnicity and histological type. More detailed and well-designed studies are still needed to confirm the role of the PROGINS allele in ovarian cancer development.

Analyze association of the progesterone receptor gene polymorphism PROGINS with ovarian cancer risk

Results conflict on the association between progesterone receptor gene (PRG) polymorphism PROGINS and ovarian cancer risk, despite wide-ranging investigations. We therefore performed a meta-analysis of 4,285 ovarian cancer cases and 6,257 controls from 11 published case-control studies. The strength of association between PROGINS polymorphism and ovarian cancer susceptibility was assessed using pooled odds ratios (ORs) with corresponding 95 % confidence intervals (CIs). The results suggest no significant associations exist between PROGINS polymorphisms and ovarian cancer risk in overall comparisons in all genetic models (T2T2 vs. T1T1: OR = 1.37, 95 % CI = 0.89-2.12, P = 0.15; T1T2 vs. T1T1:OR = 1.09, 95 % CI = 0.88-1.35, P = 0.41; T1T2 + T2T2 vs. T1T1:OR = 1.15, 95 % CI = 0.94-1.40, P = 0.17; T2T2 vs. T1 T1 + T1T2:OR = 1.34, 95 % CI = 0.87-2.07, P = 0.18). In conclusion, the results of this meta-analysis indicate that the PRG polymorphism PROGINS is not associated with ovarian cancer risk when multiple ethnic groups or regions were considered overall.

Hereditary breast and ovarian cancer susceptibility genes (review)

Women with hereditary breast and ovarian cancer (HBOC) syndrome represent a unique group who are diagnosed at a younger age and result in an increased lifetime risk for developing breast, ovarian and other cancers. This review integrates recent progress and insights into the molecular basis that underlie the HBOC syndrome. A review of English language literature was performed by searching MEDLINE published between January 1994 and October 2012. Mutations and common sequence variants in the BRCA1 and BRCA2 (BRCA) genes are responsible for the majority of HBOC syndrome. Lifetime cancer risks in BRCA mutation carriers are 60-80% for breast cancer and 20-40% for ovarian cancer. Mutations in BRCA genes cannot account for all cases of HBOC, indicating that the remaining cases can be attributed to the involvement of constitutive epimutations or other cancer susceptibility genes, which include Fanconi anemia (FA) cluster (FANCD2, FANCA and FANCC), mismatch repair (MMR) cluster (MLH1, MSH2, PMS1, PMS2 and MSH6), DNA repair cluster (ATM, ATR and CHK1/2), and tumor suppressor cluster (TP53, SKT11 and PTEN). Sporadic breast cancers with TP53 mutations or epigenetic silencing (hypermethylation), ER- and PgR-negative status, an earlier age of onset and high tumor grade resemble phenotypically BRCA1 mutated cancers termed 'BRCAness', those with no BRCA mutations but with a dysfunction of the DNA repair system. In conclusion, genetic or epigenetic loss-of-function mutations of genes that are known to be involved in the repair of DNA damage may lead to increased risk of developing a broad spectrum of breast and ovarian cancers.

Serum levels of IGF-I and BRCA penetrance: a case control study in breast cancer families

High serum levels of insulin-like growth factor I (IGF-I) are associated with an increased risk of sporadic breast cancer (BC). The aim of the present work is to evaluate the association between IGF-I and hereditary BC risk, using a case-control approach. The work represents an "ad interim" cross-sectional analysis of an ongoing study with a prospective design whose aim is to recruit a cohort of women belonging to high genetic risk families to test potential modulators of penetrance and prognosis. The odd of exposure to high serum IGF-I levels among women with a previous diagnosis of BC ("cases") was compared with the odd among unaffected "controls". The odds ratio (OR) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression, controlling for confounders. We analysed 308 women (209 cases and 99 controls) at high genetic risk of BC. The adjusted OR of BC for the upper tertile of serum IGF-I versus the lowest one was 3.5 (95%CI 1.4-8.8). Excluding from the analysis 64 women under current Tamoxifen or GnRH analogues treatment, the adjusted OR of BC became 3.7 (95%CI 1.4-9.9). The association became stronger restricting the analysis to the 161 women (97 cases and 64 controls) with a proven BRCA mutation. If confirmed by a prospective approach, the association between IGF-I and familial BC will open further options for reducing BC risk in susceptible women.

GWAS-identified colorectal cancer susceptibility locus associates with disease prognosis

PURPOSE

Extensive evidence has suggested that risk factors of cancer development may also modulate cancer clinical outcome. Recent genome-wide association (GWA) studies identified several single nucleotide polymorphisms (SNPs) predisposing to colorectal cancer (CRC). Given the pivotal importance of these variants in CRC, we sought to evaluate their associations with clinical outcomes of the disease.

EXPERIMENTAL DESIGN

In a well-characterised cohort including 380 Chinese CRC patients, we genotyped seven SNPs identified in previous multi-stage GWA studies and analysed their associations with patient recurrence and survival.

RESULTS

One SNP on chromosome 15q13, rs4779584 was associated with reduced risk of death with a hazard ratio (HR) of 0.33 (95% confidence interval [CI] 0.15-0.72, P = 0.007). Another SNP in a gene-desert region on chromosome 10p14, rs10795668, was associated with a reduced risk of recurrence with an HR of 0.55 (95% CI 0.30-1.00, P = 0.05). In a stratified analysis, this association was only evident in patients receiving chemotherapy (HR = 0.32, 95% CI 0.14-0.78, P = 0.01, log rank P = 0.004), but not in those without chemotherapy (HR = 1.08, 95% CI 0.43-2.73, P = 0.87, log rank P = 0.66). Moreover, we found that the effects of chemotherapy on CRC recurrence was only evident in patients with the variant-containing genotypes (HR = 0.35, 95% CI 0.13-0.94, P = 0.04) but not in those with the wild-type genotype of rs10795668. Further analyses indicated a borderline significant interaction effect (P interaction = 0.05) between rs10795668 and chemotherapy on patient recurrence.

CONCLUSIONS

Our data suggested that rs10795668, a CRC susceptibility variant identified by GWA studies, might be used as a biomarker to identify CRC patients with high risk of recurrence after chemotherapy.

Modification of ovarian cancer risk by BRCA1/2-interacting genes in a multicenter cohort of BRCA1/2 mutation carriers

Inherited BRCA1/2 mutations confer elevated ovarian cancer risk. Knowledge of factors that can improve ovarian cancer risk assessment in BRCA1/2 mutation carriers is important because no effective early detection for ovarian cancers exists. A cohort of 1,575 BRCA1 and 856 BRCA2 mutation carriers was used to evaluate haplotypes at ATM, BARD1, BRIP1, CTIP, MRE11, NBS1, RAD50, RAD51, and TOPBP1 in ovarian cancer risk. In BRCA1 carriers, no associations were observed with ATM, BARD1, CTIP, RAD50, RAD51, or TOPBP1. At BRIP1, an association was observed for one haplotype with a multiple testing corrected P (P(corr)) = 0.012, although no individual haplotype was significant. At MRE11, statistically significant associations were observed for one haplotype (P(corr) = 0.007). At NBS1, we observed a P(corr) = 0.024 for haplotypes. In BRCA2 carriers, no associations were observed with CTIP, NBS1, RAD50, or TOPBP1. Rare haplotypes at ATM (P(corr) = 0.044) and BARD1 (P(corr) = 0.012) were associated with ovarian cancer risk. At BRIP1, two common haplotypes were significantly associated with ovarian cancer risk (P(corr) = 0.011). At MRE11, we observed a significant haplotype association (P(corr) = 0.012), and at RAD51, one common haplotype was significantly associated with ovarian cancer risk (P(corr) = 0.026). Variants in genes that interact biologically withBRCA1 and/or BRCA2 may be associated with modified ovarian cancer risk in women who carry BRCA1/2 mutations.

Gene polymorphisms that may influence the biological effects of progestins

Many of the biological actions of progestins depend on binding to intracellular receptors and through a long chain of events to subsequent stimulation of transcriptional activity and protein synthesis. This process requires at least a few hours in time and many different proteins called coregulators do play a role after binding to the receptor. Evidence for polymorphisms in the gene coding for the PR has been obtained and many studies have already attempted to show associations between particular polymorphisms and human diseases. However, at present no consistent and conclusive picture has emerged on clinically important associations. Studies on links between polymorphisms in genes coding for coregulators are just beginning. The second pathway, the so-called non-genomic actions, is related to rapid effects of progestins that occur within minutes. At this moment a number of different membrane bound receptors have been identified. No data are available yet on polymorphisms in genes coding for these proteins or to link any of these membrane receptors to specific human pathology.

Progesterone receptor (PROGINS) polymorphism and the risk of ovarian cancer

The present case-control study evaluates the role of the progesterone receptor (PR) polymorphism known as PROGINS as a risk factor for ovarian cancer development and investigates the association between these genetic variants and clinical/pathologic variables of ovarian cancer. PROGINS polymorphism was examined, by polymerase chain reaction, in a total of 80 patients with ovarian cancer and 282 control subjects. The frequencies of PROGINS polymorphism T1/T1, T1/T2, and T2/T2 were 71.3, 15.0 and 13.8% in ovarian cancer patients and 78.37, 21.63 and 0% in controls, respectively. The chi(2)-test showed a higher incidence of the T2/T2 genotype (P=0.001) in the ovarian cancer group. In addition, women carrying a mutated allele (T2) showed approximately 2.2 times higher risk of ovarian cancer development as compared to women who have a variant allele (odds ratio (OR)=2.2; 95% CI=1.80-3.54). Regarding the clinical and pathologic findings observed within the cancer group, there was a significant correlation between PROGINS polymorphism and patients with a familial history (chi(2)=6.776; P=0.009; Fischer exact test, P=0.01). In this regard, patients with familial antecedents have a 4.7 times higher likelihood to have at least one risk allele (T2) as compared with patients without familial antecedents (OR=4.69; 95% CI=1.38-15.87). No correlations were observed among the other variables. These data suggest that the PROGINS polymorphism T2/T2 genotype might be associated with an increased risk of ovarian cancer.

Genetic susceptibility for breast cancer: How many more genes to be found?

Today, breast cancer is the most commonly occurring cancer among women. It accounts for 22% of all female cancers and the estimated annual incidence of breast cancer worldwide is about one million cases. Many risk factors have been identified but a positive family history remains among the most important ones established for breast cancer, with first-degree relatives of patients having an approximately two-fold elevated risk. It is currently estimated that approximately 20-25% of this risk is explained by known breast cancer susceptibility genes, mostly those conferring high risks, such as BRCA1 and BRCA2. However, these genes explain less than 5% of the total breast cancer incidence, even though several studies have suggested that the proportion of breast cancer that can be attributed to a genetic factor may be as high as 30%. It is thus likely that there are still breast cancer susceptibility genes to be found. It is presently not known how many such genes there still are, nor how many will fall into the class of rare high-risk (e.g. BRCAx) or of common low-risk susceptibility genes, nor if and how these factors interact with each other to cause susceptibility (a polygenic model). In this review we will address this question and discuss the different undertaken approaches used in identifying new breast cancer susceptibility genes, such as (genome-wide) linkage analysis, CGH, LOH, association studies and global gene expression analysis.

Modifiers of risk of hereditary breast cancer

Mutations in the BRCA1 and BRCA2 genes confer a high lifetime risk of breast and ovarian cancer. The risk varies from individual to individual, and it appears that the risk has increased in recent generations. These observations imply that non-genetic factors may modify the inherited risk. To date, the factors that appear most strongly to modify the risk include reproductive histories and exogenous hormones. Oral contraceptives are associated with a profound reduction in the risk of ovarian cancer, and with little or no increase in the risk of breast cancer. Other modifying factors include age of menarche, parity, breastfeeding and oophorectomy. The effect of parity is different in BRCA1 and BRCA2 carriers. Multiparity appears to be protective in BRCA1 carriers, but is associated with an increase in risk in BRCA2 carriers. Oophorectomy has been associated with reductions in both the risk of breast and ovarian cancer. Knowledge of these risk factors will be useful for managing risk and for developing prevention strategies.

Two functionally relevant polymorphisms in the human progesterone receptor gene (+331 G/A and progins) and the predisposition for breast and/or ovarian cancer

OBJECTIVE

Two polymorphisms affecting either expression (+331 G/A) or transcriptional activity (progins) of the progesterone receptor have been described. No clear correlation between either polymorphism and breast or ovarian cancer has been shown. Our objective is to clarify whether the two progesterone receptor polymorphisms modify the risk for breast or ovarian cancer.

METHODS

Healthy women and women suffering from either ovarian or breast cancer were enrolled in a case-control-based study to compare the frequencies of women carrying either one, both or none of the two polymorphisms. Patient and control populations resided in the same region of South Germany. PCR-RFLP analysis was used to determine the polymorphic alleles.

RESULTS

Women diagnosed with ovarian cancer showed a not significant increased frequency of +331 A carriers and a significantly increased frequency of progins carriers. Both polymorphisms appeared to be associated with a significantly increased risk for the disease in women below 51 years [OR: 4.1 (CI: 1.2-13.9) and 3.2 (CI: 1.1-9.1), respectively]. No association was detected between either of the two polymorphisms and breast cancer. Among ovarian and breast cancer patients, the number of individuals carrying both rare polymorphic alleles was significantly higher compared to healthy women.

CONCLUSIONS

Our findings support the hypothesis that low penetrant polymorphisms of progesterone receptor may modify the risk for ovarian cancer. Our data do not allow drawing a clear conclusion on the risk for breast cancer.

BRCA1 and BRCA2: the genetic testing and the current management options for mutation carriers

Approximately 5-10% of breast carcinomas and 10% of ovarian carcinomas are ascribable to a genetic susceptibility. Of these, about 40% are related to genetic mutations in the genes BRCA1 and BRCA2. Despite the increasing demand for genetic testing arising from the patients and their relatives, the genetic testing can be offered yet only to individuals belonging to high-risk families in which the probability that there is a germline mutation in a BRCA gene is high and thus cancer occurrence is likely the expression of a highly penetrant genetic predisposition. In this article, we review how the current knowledge on the biological mechanisms underlying BRCA1 and BRCA2 dysfunction may contribute to the understanding of breast and ovarian cancer predisposition. The most currently employed methods for genetic testing are critically overviewed, together with some indications for the interpretation of the test outcome and the clinical management of mutation carriers.

Molecular mechanisms and biological plausibility underlying the malignant transformation of endometriosis: a critical analysis

Although population-based studies have unequivocally reported an increased risk of ovarian cancer in women with endometriosis, the biological evidence supporting the idea of endometriosis as a preneoplastic condition is scanty and not well substantiated. The fundamental features of human neoplasms (monoclonal growth, genetic changes, mutations in tumour suppressor genes and replicative advantage) have been evaluated in endometriotic lesions but results obtained are discordant. It is plausible that ectopic glands may expand monoclonally but the entity of this phenomenon is debated. According to some allelotyping studies, from one-third to one-half of endometriosis lesions would harbour somatic genetic changes in chromosomal regions supposed to contain genes involved in ovarian tumourigenesis, especially for the endometrioid histotype. These findings would be consistent with the progression model for carcinogenesis from the benign precursor to ovarian cancer but they could not be unequivocally replicated. Gene mutational studies are rare in this context. A single group has found missense mutations and deletions of PTEN gene in about 20% of ovarian endometriotic cysts. Moreover, in a model of genetically engineered mice harbouring an oncogenic allele of K-ras resulting in benign lesions reminiscent of endometriosis, a conditional deletion of PTEN caused the progression towards the endometrioid tumour. Based on these data, the causal link between endometriosis and ovarian endometrioid/clear cell carcinomas remains to be defined both in terms of entity of association and of underlying molecular mechanisms.

Association between polymorphisms in the progesterone receptor gene and endometriosis

The progesterone receptor (PR) is a candidate gene for the development of endometriosis, a complex disease with strong hormonal features, common in women of reproductive age. We typed the 306 base pair Alu insertion (AluIns) polymorphism in intron G of PR in 101 individuals, estimated linkage disequilibrium (LD) between five single-nucleotide polymorphisms (SNPs) across the PR locus in 980 Australian triads (endometriosis case and two parents) and used transmission disequilibrium testing (TDT) for association with endometriosis. The five SNPs showed strong pairwise LD, and the AluIns was highly correlated with proximal SNPs rs1042839 (delta2 = 0.877, D9 = 1.00, P < 0.0001) and rs500760 (delta2 = 0.438, D9 = 0.942, P < 0.0001). TDT showed weak evidence of allelic association between endometriosis and rs500760 (P = 0.027) but not in the expected direction. We identified a common susceptibility haplotype GGGCA across the five SNPs (P = 0.0167) in the whole sample, but likelihood ratio testing of haplotype transmission and non-transmission of the AluIns and flanking SNPs showed no significant pattern. Further, analysis of our results pooled with those from two previous studies suggested that neither the T2 allele of the AluIns nor the T1/T2 genotype was associated with endometriosis.

Genetic variation in the progesterone receptor gene and ovarian cancer risk

Evidence suggests a role for progesterone in ovarian cancer development. Progesterone exerts its effect on target cells by interacting with its receptor. Thus, genetic variations that may cause alterations in the biologic functions of the progesterone receptor can potentially contribute to individual susceptibility to ovarian cancer. Using a population-based, case-control study, the authors genotyped four polymorphisms in the progesterone receptor gene (+44C/T, +331G/A, G393G, V660L) and inferred haplotypes in 987 ovarian cancer cases and 1,034 controls living in New Hampshire and eastern Massachusetts (May 1992-November 2002). Odds ratios and 95% confidence intervals were calculated to evaluate associations with ovarian cancer. No associations were observed between the +44C/T, +331G/A, and G393G polymorphisms and ovarian cancer. However, an inverse association was observed between the V660L variant and ovarian cancer (odds ratio = 0.70, 95% confidence interval: 0.57, 0.85). Associations remained after adjustment for potential confounders. Five haplotypes occurred with greater than 5% frequency, and the haplotype carrying the V660L variant had a significant association with ovarian cancer (odds ratio = 0.76, 95% confidence interval: 0.62, 0.92). Associations were similar after stratifying by ovarian cancer histologies and risk factors.

Investigation of hormone receptor genes in migraine

Migraine is a common neurological condition with a complex mode of inheritance. Steroid hormones have long been implicated in migraine, although their role remains unclear. Our investigation considered that genes involved in hormonal pathways may play a role in migraine susceptibility. We therefore investigated the androgen receptor (AR) CAG repeat, and the progesterone receptor (PR) PROGINS insert by cross-sectional association analysis. The results showed no association with the AR CAG repeat in our study group of 275 migraineurs and 275 unrelated controls. Results of the PR PROGINS analysis showed a significant difference in the same cohort, and in an independent follow-up study population of 300 migraineurs and 300 unrelated controls. Analysis of the genotypic risk groups of both populations together indicated that individuals who carried the PROGINS insert were 1.8 times more likely to suffer migraine. Interaction analysis of the PROGINS variant with our previously reported associated ESR1 594A variant showed that individuals who possessed at least one copy of both risk alleles were 3.2 times more likely to suffer migraine. Hence, variants of these steroid hormone receptor genes appear to act synergistically to increase the risk of migraine by a factor of three.

Correlates of obesity in postmenopausal women with breast cancer: comparison of genetic, demographic, disease-related, life history and dietary factors

BACKGROUND

Obesity in women has been associated with a variety of factors, including genetic predisposition, social class, early age at menarche, exercise, alcohol consumption and diet. Obesity is a risk factor for the occurrence and the recurrence of breast cancer in postmenopausal women, perhaps because of increased exposure to estrogen, insulin and insulin-like growth factors (IGFs). The progesterone receptor (PR) and the steroid hormone receptor coactivator pCIP/ACTR/AIB1/TRAM1/RAC3 (AIB1) are hypothesized to mediate signaling crosstalk between these hormonal pathways. Polymorphisms in both genes have been described and their association with breast cancer risk reported. If genetic factors contribute to obesity, and the PR and AIB1 genes influence estrogenic, insulin and IGF pathways, then genetic patterns resulting from PR and AIB1 polymorphisms may be associated with obesity in postmenopausal women.

OBJECTIVE

We compared the PR and AIB1 genotypes of postmenopausal women with breast cancer with demographic, disease-related, reproductive, lifestyle and dietary variables in terms of the strength of their relationship with obesity (BMI> or =30 kg/m2).

SUBJECTS

A total of 301 postmenopausal women previously diagnosed with Stage I, II or IIIA breast cancer, who are enrolled in the Women's Healthy Eating and Living (WHEL) study (age: 34.5-70.8 y, BMI: 17.8-54.6 kg/m2).

MEASUREMENTS

The PR polymorphism PROGINS was identified by PCR. The length of the AIB1 polyglutamine repeat was determined by PCR and nondenaturing gel electrophoresis or DNA sequencing. BMI was obtained at the baseline clinic visit upon entry into the WHEL study. Information about date of diagnosis, stage of disease, tumor hormone receptor status and adjuvant treatment received were obtained from medical records. Reproductive, menstrual history, demographic, family history of cancer, smoking history and exercise frequency and intensity information were obtained from questionnaires. Dietary and alcohol intake data came from four 24-h telephone recalls of food intake obtained at the study entry.

RESULTS

The combined inheritance of PROGINS A1/A1 and AIB1 28/29, 28/30, 28/31, 29/29 or 29/30 (AIB1 LG) genotypes (adjusted odds ratio (OR)=2.22 (95% confidence interval 1.25-3.93)) and early age at menarche (<12 y) (adjusted OR=2.34 (1.12-4.86)) were each associated with the risk for obesity. Current use of tamoxifen (adjusted OR=0.49 (0.28-0.87)) and an alcohol intake > or =10 g/day (adjusted OR=0.28 (0.11-0.77)) were inversely associated with BMI > or =30 kg/m2.

CONCLUSION

Early age at menarche and a PROGINS A1/A1+AIB1 LG genetic pattern had comparable levels of association with obesity in this cross-sectional sample of postmenopausal women with breast cancer. Since this was a cross-sectional rather than a case-control design, the association between PROGINS and AIB1 genotype and obesity found in this sample should be considered preliminary, and must be re-evaluated with a new and larger sample.

Endometriosis and ovarian cancer: thoughts on shared pathophysiology

BACKGROUND

Endometriosis appears to predispose to ovarian cancer. How this may occur has been little discussed.

STUDY DESIGN

This article reviews the English language literature for in vitro, animal, clinical, and epidemiologic studies linking the two conditions.

RESULTS

Pathology case series consistently report endometrioid and clear cell types of ovarian cancer arising from endometriotic foci. Epidemiologic studies have been consistent with this association. There are also marked similarities between the proposed etiology of ovarian cancer and the observed pathophysiology of endometriosis. Specifically, both are characterized by immune alterations. Both conditions are promoted by estrogen excess and by progesterone deficit. Finally, steroid hormones interacting with the immune system may stimulate both endometriosis and ovarian cancer. I propose that the biology common to endometriosis and ovarian cancer represents not just a parallelism, but instead a causal pathway: aberrant immune function, fed by and feeding on estrogens, unbalanced by progesterone, may create a positive feed-forward loop that enhances the growth and invasiveness of endometriosis and promotes its malignant transformation.

CONCLUSIONS

The same pathophysiology may orchestrate the progression of endometriosis and its transformation to endometroid and clear cell ovarian neoplasias. This notion of a unifying biology suggests a directed approach to future research and identifies possible chemoprevention strategies for women with endometriosis.

Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case Series unselected for family history: a combined analysis of 22 studies

Germline mutations in BRCA1 and BRCA2 confer high risks of breast and ovarian cancer, but the average magnitude of these risks is uncertain and may depend on the context. Estimates based on multiple-case families may be enriched for mutations of higher risk and/or other familial risk factors, whereas risk estimates from studies based on cases unselected for family history have been imprecise. We pooled pedigree data from 22 studies involving 8,139 index case patients unselected for family history with female (86%) or male (2%) breast cancer or epithelial ovarian cancer (12%), 500 of whom had been found to carry a germline mutation in BRCA1 or BRCA2. Breast and ovarian cancer incidence rates for mutation carriers were estimated using a modified segregation analysis, based on the occurrence of these cancers in the relatives of mutation-carrying index case patients. The average cumulative risks in BRCA1-mutation carriers by age 70 years were 65% (95% confidence interval 44%-78%) for breast cancer and 39% (18%-54%) for ovarian cancer. The corresponding estimates for BRCA2 were 45% (31%-56%) and 11% (2.4%-19%). Relative risks of breast cancer declined significantly with age for BRCA1-mutation carriers (P trend.0012) but not for BRCA2-mutation carriers. Risks in carriers were higher when based on index breast cancer cases diagnosed at <35 years of age. We found some evidence for a reduction in risk in women from earlier birth cohorts and for variation in risk by mutation position for both genes. The pattern of cancer risks was similar to those found in multiple-case families, but their absolute magnitudes were lower, particularly for BRCA2. The variation in risk by age at diagnosis of index case is consistent with the effects of other genes modifying cancer risk in carriers.