Genetic predisposition to breast cancer

Breast MRI Screening in Patients with Increased Familial and/or Genetic Risk for Breast Cancer: A Preliminary Experience

Aims and background

Breast cancer is the most common cancer affecting women, and it is associated with or due to a genetic predisposition in 5%-10% of the cases. Owing to the higher risk of developing breast cancer and the early onset of the disease in women proved or suspected to be carriers of a breast cancer susceptibility gene, a dedicated screening should be offered as a less invasive approach with the otherwise suggested prophylactic mastectomy. This should be optimized in order to overcome the limitations of conventional breast imaging with the application of new technologies such as breast magnetic resonance imaging.

Methods

A diagnostic protocol for routine control in patients at high risk of developing breast cancer has been prepared. Within a 7-month period, 23 patients suspected or proved to carry a breast cancer susceptibility gene underwent breast magnetic resonance imaging.

Results

Four breast cancers were identified with breast magnetic resonance imaging. In these cases, mammography was negative because of the density of the parenchyma or for its fibroglandular pattern. Ultrasound was negative in 2 cases, not specific for malignancy in 1 case, and considered as only possibly malignant but with biopsy recommendation on the basis of magnetic resonance findings in the last one. Clinical analysis was positive for a mass in 2 cases.

Conclusions

The accuracy of breast magnetic resonance imaging is known to be higher than that of conventional imaging in the study of breast parenchyma. High spatial resolution, no breast density influence and multiplanarity can give more detailed information about the smaller lesions and the right extension of the disease. Preliminary studies where breast magnetic resonance imaging is performed in addition to mammography within this group of patients are encouraging. We also believe that the application of breast magnetic resonance imaging can be very useful in the detection of cancer as early as possible with the aim to obtain the highest chance of survival after treatment.

Identification of twenty-nine novel germline unclassified variants of BRCA1 and BRCA2 genes in 1400 Italian individuals

OBJECTIVES

Breast and/or ovarian cancers are complex multifactorial diseases caused by interaction of both genetic and non-genetic factors and characterized by predisposition to inheritance. BRCA1 and BRCA2 genes are the most clinically involved with these kinds of cancer and the spectrum of variants affecting these genes is very wide. In fact, point variants, large or small insertions/deletions, genomic rearrangements can be found in these patients, although a large number of variants with uncertain biological and clinical significance continues to be identified. Next-generation sequencing (NGS) technology is actually the most powerful tool for the discovering of causative mutations and novel disease genes, moreover it allows to make a rapid diagnosis of genetic variants giving fast, inexpensive and detailed genetic information.

MATERIAL AND METHODS

In this study, we report the screening of BRCA1 and BRCA2 genes on 1400 consecutive Caucasian patients with breast and/or ovarian cancer history or family risk, attending the oncogenetic ambulatory at the Foundation Policlinico Agostino Gemelli in Rome.

RESULTS

We describe twenty-nine novel BRCA1 and BRCA2 variants detected in Italian individuals suffering from hereditary breast and ovarian cancer syndrome (HBOC).

CONCLUSION

Data regarding novel variants can provide useful information not only at epidemiological but also at clinical level, allowing for the better managing of breast and ovarian cancer patients and their family members.

High frequency of the recurrent c.1310_1313delAAGA BRCA2 mutation in the North-East of Morocco and implication for hereditary breast-ovarian cancer prevention and control

Background

To date, a limited number of BRCA1/2 germline mutations have been reported in hereditary breast and/or ovarian cancer in the Moroccan population. Less than 20 different mutations of these two genes have been identified in Moroccan patients, and recently we reported a further BRCA2 mutation (c.1310_1313delAAGA; p.Lys437IlefsX22) in three unrelated patients, all from the North-East of the country. We aimed in this study to evaluate the frequency and geographic distribution of this BRCA2 frameshift mutation, in order to access its use as the first-line BRCA genetic testing strategy for Moroccan patients. We enrolled in this study 122 patients from different regions of Morocco, with suggestive inherited predisposition to breast and ovarian cancers. All subjects gave written informed consent to BRCA1/2 genetic testing. According to available resources of our lab and enrolled families, 51 patients were analyzed by the conventional individual exon-by-exon Sanger sequencing, 23 patients were able to benefit from a BRCA next generation sequencing and a target screening for exon 10 of BRCA2 gene was performed in 48 patients.

Results

Overall, and among the 122 patients analyzed for at least the exon 10 of the BRCA2 gene, the c.1310_1313delAAGA frameshift mutation was found in 14 patients. Genealogic investigation revealed that all carriers of this mutation shared the same geographic origin and were descendants of the North-East of Morocco.

Discussion

In this study, we highlighted that c.1310_1313delAAGA mutation of BRCA2 gene is recurrent with high frequency in patients from the North-East region of Morocco. Therefore, we propose to use, in public health strategies, the detection of this mutation as the first-line screening tests in patients with breast and ovarian cancer originated from this region.

First application of next-generation sequencing in Moroccan breast/ovarian cancer families and report of a novel frameshift mutation of the BRCA1 gene

At present, breast cancer is the most common type of cancer in females. The majority of cases are sporadic, but 5-10% are due to an inherited predisposition to develop breast and ovarian cancers, which are transmitted as an autosomal dominant form with incomplete penetrance. The beneficial effects of clinical genetic testing, including next generation sequencing (NGS) for BRCA1/2 mutations, is major; in particular, it benefits the care of patients and the counseling of relatives that are at risk of breast cancer, in order to reduce breast cancer mortality. BRCA genetic testing was performed in 15 patients with breast cancer and a family with positivity for the heterozygous c.6428C>A mutation of the BRCA2 gene. Informed consent was obtained from all the subjects. Genomic DNAs were extracted and the NGS for genes was performed using the Ion Torrent Personal Genome Machine (PGM) with a 316 chip. The reads were aligned with the human reference HG19 genome to elucidate variants in the BRCA1 and BRCA2 genes. Mutations detected by the PGM platform were confirmed by target direct Sanger sequencing on a second patient DNA sample. In total, 4 BRCA variants were identified in 6 families by NGS. Of these, 3 mutations had been previously reported: c.2126insA of BRCA1, and c.1310_1313delAAGA and c.7235insG of BRCA2. The fourth variant, c.3453delT in BRCA1, has, to the best of our knowledge, never been previously reported. The present study is the first to apply NGS of the BRCA1 and BRCA2 genes to a Moroccan population, prompting additional investigation into local founder mutations and variant characteristics in the region. The variants with no clear clinical significance may present a diagnostic challenge when performing targeted resequencing. These results confirm that an NGS approach based on Ampliseq libraries and PGM sequencing is a highly efficient, speedy and high-throughput mutation detection method, which may be preferable in lower income countries.

Novel nonsense mutation of BRCA2 gene in a Moroccan man with familial breast cancer

BACKGROUND

Breast cancer is the most common cancer in women worldwide. About 5 to 10% of cases are due to an inherited predisposition in two major genes, BRCA1 and BRCA2, transmitted as an autosomal dominant form. Male breast cancer is rare and is mainly due to BRCA2 than BRCA1 germline mutations.

OBJECTIVE

Molecular study of BRCA2 gene in man with familial breast cancer.

METHODS

PCR and direct sequencing of BRCA2 gene.

RESULTS

Identification of novel heterozygous germline mutation c.6428C>A ; p.Ser2143Stop of BRCA2 gene.

Novel insights into breast cancer genetic variance through RNA sequencing

Using RNA sequencing of triple-negative breast cancer (TNBC), non-TBNC and HER2-positive breast cancer sub-types, here we report novel expressed variants, allelic prevalence and abundance, and coexpression with other variation, and splicing signatures. To reveal the most prevalent variant alleles, we overlaid our findings with cancer- and population-based datasets and validated a subset of novel variants of cancer-related genes: ESRP2, GBP1, TPP1, MAD2L1BP, GLUD2 and SLC30A8. As a proof-of-principle, we demonstrated that a rare substitution in the splicing coordinator ESRP2 (R353Q) impairs its ability to bind to its substrate FGFR2 pre-mRNA. In addition, we describe novel SNPs and INDELs in cancer relevant genes with no prior reported association of point mutations with cancer, such as MTAP and MAGED1. For the first time, this study illustrates the power of RNA-sequencing in revealing the variation landscape of breast transcriptome and exemplifies analytical strategies to search regulatory interactions among cancer relevant molecules.

Breast cancer risk analysis: A genetic epidemiology service for families

Breast Cancer Risk Analysis, a service for women with breast cancer and their families, makes use of information drawn from fields such as genetics, epidemiology, and counseling. Its aim is to provide individuals with background information and information regarding the etiology and risks of breast cancer. Based on this information, individuals are helped to make appropriate decisions pertaining to treatment and follow-up. While making use of some of the information and processes used in genetic counseling, Breast Cancer Risk Analysis differs from most types of genetic counseling for reproductive decisions. Some of these differences are discussed here.

Patient preferences and National Health Service costs: a cost-consequences analysis of cancer genetic services

The study has three aims; firstly to establish if, having been informed of their risk status and that gene testing is inappropriate for them, low and moderate risk patients have misunderstood or failed to grasp this and want a test that is inappropriate for them. Secondly, to elicit patients' willingness to pay for cancer genetic services. Thirdly, to ascertain the aspects of cancer genetics services that are important to high risk patients and present service configurations prioritised in terms of preferences accompanied by their costs (cost-consequences analysis). Patient preferences were gathered from 120 patients returning a self-administered discrete choice questionnaire issued post genetic risk assessment. Patients at low and moderate risk of developing breast cancer desired inappropriate testing. Patients at high, moderate and low risk of developing genetic cancer were willing to pay up to 3,000 pounds for genetic serviced, which exceeds the current estimated cost of providing testing and counselling. Counselling by a genetics associate accompanied by favourable levels of other attributes provided high utility and substantial cost savings.

MR Imaging for Surveillance of Women at High Familial Risk for Breast Cancer

The adequate management of individuals who carry a high lifetime risk for breast cancer is still an unsettled issue. This holds especially true for subjects with documented or suspected germline mutation of a breast cancer susceptibility gene. These women face a lifetime risk for breast cancer of up to 80%, which is, of course, significant. Still, this means that approximately one fifth of women never develop the disease. The perceived mutilating effects of preventive mastectomy make the decision for surgical prevention difficult for most women. Secondary prevention aims at identifying familial breast cancer at the earliest possible stage. During recent years, considerable evidence has been accumulated that breast MR imaging is substantially more sensitive than mammography and breast ultrasound regarding the identification of familial breast cancer. It should be considered an integral part of a surveillance program for women at increased familial risk for breast cancer, be it with or without documented mutation of a breast cancer susceptibility gene.

Management of women at high risk for breast cancer: New imaging beyond mammography

The management of women with an increased lifetime risk of breast cancer is a difficult task. This is especially true for women with a documented mutation in a breast cancer susceptibility gene (BRCA), and also for those who tested negative for a mutation, but have a family history that is suggestive of familial breast cancer. Primary prevention by prophylactic mastectomy has been shown to reduce breast cancer incidence in these women, but this intervention is still not considered a "first-line" option in the majority of guidelines. Instead, secondary prevention (intensified surveillance) is recommended. However, due to the early onset of familial breast cancer, screening must start at a substantially younger age than in women at average risk. This, together with the fact that familial breast cancers may differ from sporadic cancers in many aspects, will have a significant impact on the design and on the success rates of surveillance protocols. This article describes the different management options that exist for women at increased genetic risk and provides a survey of the current evidence regarding mammographic and non-mammographic imaging techniques. The conclusion is that mammographic screening, with or without concomitant ultrasound and clinical breast examination, is probably not sufficient to ensure an early diagnosis of familial breast cancer. If MRI is integrated in surveillance programs, early diagnosis seems to be possible. Still, the efficacy of screening even with MRI is unclear in terms of morbidity and mortality, and this lack of evidence must be communicated to women at high genetic risk.

A micro costing of NHS cancer genetic services

This paper presents the first full micro costing of a commonly used cancer genetic counselling and testing protocol used in the UK. Costs were estimated for the Cardiff clinic of the Cancer Genetics Service in Wales by issuing a questionnaire to all staff, conducting an audit of clinic rooms and equipment and obtaining gross unit costs from the finance department. A total of 22 distinct event pathways were identified for patients at risk of developing breast, ovarian, breast and ovarian or colorectal cancer. The mean cost per patient were pound sterling 97- pound sterling 151 for patients at moderate risk, pound sterling 975- pound sterling 3072 for patients at high risk of developing colorectal cancer and pound sterling 675- pound sterling 2909 for patients at high risk of developing breast or ovarian cancer. The most expensive element of cancer genetic services was labour. Labour costs were dependent upon the amount of labour, staff grade, number of counsellors used and the proportion of staff time devoted to indirect patient contact. With the growing demand for cancer genetic services and the growing number of national and regional cancer genetic centers, there is a need for the different protocols being used to be thoroughly evaluated in terms of costs and outcomes.

Current comprehensive assessment and management of women at increased risk for breast cancer

The potential for reducing the risk of breast cancer through selective estrogen receptor modulators, aromatase inhibitors, and surgery has generated interest in the use of quantitative models of risk assessment. With the addition of ductal lavage cytology to traditional epidemiologic risk factors, a discovery of cellular atypia can result in refinement of assigned risk values, while simultaneously optimizing patient selection for selective estrogen receptor modulators utilization. In view of increasing complexity in this arena, a Risk Assessment Working Group was formed to outline management strategies for the patient at an elevated risk for the development of breast cancer. No longer a statistical exercise, quantitative risk assessment is part of basic breast care and comprehensive management includes a discussion of the following: ductal lavage for improved risk stratification, multiple options for risk reduction, and high risk surveillance strategies that might incorporate investigational imaging protocols.

Identification of HRPAP20

The prolactin (PRL)-dependent rat Nb2 T lymphoma is a valuable model for investigation of molecular mechanisms that underlie tumor progression in hormone-dependent cancers. mRNA differential display was used to screen for novel gene products expressed in hormone-stimulated or differentiating agent-treated Nb2 sublines. From numerous transcripts identified, DNA sequencing and GenBank analysis revealed a novel 289-bp fragment. Using 5'-rapid amplification of complementary ends-PCR, this fragment was used to clone a unique 2117-bp cDNA, designated HRPAP20 (hormone-regulated proliferation-associated protein), in rat lymphoma cells. Computer-assisted sequence analysis revealed a single open reading frame that encoded a putative 20.2-kDa protein. The effect of hormone stimulation to alter expression of HRPAP20 was evaluated by Northern blot analysis of total RNA obtained from PRL-stimulated, lactogen-dependent Nb2-11 cells. Quiescent cells, synchronized in the G(0)-G(1) phase of cell cycle, exhibited reduced HRPAP20 expression compared with exponentially proliferating cultures. The addition of mitogenic concentrations of PRL to stationary cells increased HRPAP20 mRNA accumulation within 4-6 h, corresponding to G(1) cell cycle progression. Immunoblot analysis showed that PRL also increased HRPAP20 protein levels within 4 h. In addition, PRL stimulated serine phosphorylation of the HRPAP20 protein with a similar kinetic pattern. Stable transfection of the HRPAP20 cDNA into Nb2-11 cells significantly (P < 0.01) increased proliferation in the absence of hormonal stimulation and inhibited apoptosis induced by lactogen deprivation (P < 0.001). In the hormone-independent and highly malignant Nb2-SFJCD1 subline, the constitutive expression of HRPAP20 was markedly reduced by exposure of the cells to dietary differentiating agents (butyrate, retinoic acid, and vitamin D(3)). After removal of these substances, PRL stimulated its expression in a manner similar to that observed in PRL-dependent Nb2-11 cells. HRPAP20 expression was also evaluated in MCF-7 cells. Its expression was detectable in quiescent cultures; addition of PRL significantly (P < 0.05) increased HRPAP20 during G(1) cell cycle progression. Exposure of the cells to butyrate or retinoic acid reduced HRPAP20 expression, similar to the effects of these substances in the malignant rat lymphoma. Stable transfection of HRPAP20 into MCF-7 cells significantly (P < 0.006) increased proliferation in the absence of hormone stimulation and augmented survival in the absence of serum (P < 0.05). We conclude that HRPAP20 is a phosphoprotein that is required for proliferation and survival of hormone-dependent tumor cells.

BRCA1 expression in canine mammary dysplasias and tumours: relationship with prognostic variables

BRCA1 is a nuclear phosphoprotein that participates in the regulation of the cell cycle. The role of the BRCA1 gene in canine mammary tissue and mammary tumours has not been studied. The present study examined immunohistochemically the expression and intracellular distribution of BRCA1 protein in two normal, seven dysplastic and 44 neoplastic canine mammary glands and its relationship with clinical and pathological variables and other prognostic parameters. Strong nuclear immunolabelling of BRCA1 protein was observed in the epithelial cells of the normal mammary glands and mammary dysplasias. The majority of benign tumours, and more especially of malignant tumours, showed a significant reduction in the nuclear expression of BRCA1 protein and an increase in cytoplasmic expression. Loss of BRCA1 expression was associated with high proliferation marker Ki-67 and ER-alpha negative tumours. The reduction and aberrant distribution of BRCA1 in canine mammary tumours were significantly associated with malignant characteristics. The results may indicate that BRCA1 has a role in the malignant behaviour of these tumours.

Loss of BRCA1 expression in sporadic male breast carcinoma

BRCA1 protein is normally expressed in the nuclei of breast epithelial cells and functions as a negative regulator of the cell cycle. Mutations of BRCA1 gene have been associated with familial breast carcinomas. Although somatic mutations have not been demonstrated in sporadic breast carcinomas, loss of nuclear expression of BRCA1 protein has been correlated with high-grade, infiltrating breast carcinomas in females. We have investigated the expression of BRCA1 protein in a series of 26 infiltrating carcinomas of male breast and correlated the results with a variety of clinicopathological parameters. Immunohistochemical analysis demonstrated decreased expression of BRCA1 in all carcinomas compared to normal breast epithelium. The median survival was 8 years in patients with minimal loss of BRCA1 expression while it was 1.5 years in patients with marked loss of this protein. Marked loss of BRCA1 protein was also associated with increased cell proliferation. These results suggest that BRCA1 plays a similar role in both male and female breast carcinoma and Joss of this protein is associated with poor prognosis.

Magnetic resonance imaging of the breast

BACKGROUND

Magnetic resonance imaging (MRI) has the potential to become a useful adjunct in breast imaging. Contrast-enhanced breast MRI has demonstrated a high sensitivity in the detection of invasive breast cancer. In clinical studies, breast MRI has often altered the course of patient care. Although promising results have been generated, MRI of the breast is currently in a development stage.

METHODS

The authors reviewed the literature on the potential indications, sensitivity, specificity, and limitations of MRI of the breast.

RESULTS

Reported advantages of MRI of the breast over conventional imaging techniques include improved staging and treatment planning, enhanced evaluation of the augmented breast, better detection of recurrence, and improved screening of high-risk women. Contrast-enhanced breast MRI is a sensitive modality for detecting breast cancer, but its variable specificity is a major limitation.

CONCLUSIONS

MRI of the breast is emerging as a valuable adjunct to mammography and sonography for specific clinical indications. Additional clinical studies that define indications, interpretation criteria, imaging parameters, and cost effectiveness are needed. A multi-institutional study designed to address these issues is in progress.

Breast MR imaging screening in 192 women proved or suspected to be carriers of a breast cancer susceptibility gene: preliminary results

PURPOSE

To compare magnetic resonance (MR) imaging with conventional imaging in screening high-risk women.

MATERIALS AND METHODS

This prospective trial included 192 asymptomatic and six symptomatic women who, on the basis of personal or family history or genetic analysis, were suspected or proved to carry a breast cancer susceptibility gene.

RESULTS

Fifteen breast cancers were identified: nine in the 192 asymptomatic women (six in the first and three in the second screening round) and six in the symptomatic patients. Concerning the asymptomatic women, four of the nine breast cancers were detected and correctly classified with mammography and ultrasonography (US) combined; another two cancers were visible as well-circumscribed masses and were diagnosed as fibroadenomas. MR imaging allowed the correct classification and local staging of all nine cancers. In 105 asymptomatic women with validation of the 1st-year screening results, the sensitivities of mammography, US, and MR imaging were 33%, 33% (mammography and US combined, 44%), and 100%, respectively; the positive predictive values were 30%, 12%, and 64%, respectively.

CONCLUSION

The accuracy of MR imaging is significantly higher than that of conventional imaging in screening high-risk women. Difficulties can be caused by an atypical manifestation of hereditary breast cancers at both conventional and MR imaging and by contrast material enhancement associated with hormonal stimulation.

Possible retroviral etiology of human breast cancer

Since the discovery in the early 1980s that retroviruses are pathogenic to man, the mouse mammary tumor viruses (MMTVs) received great attention. Studies of MMTVs allowed considerable insights into the mechanisms at work in breast tumorigenesis. MMTVs are essentially insertional mutagenes. Numerous oncogenes have been found altered by MMTVs, either specific for MMTVs or not. However, despite considerable attempts, the involvement of MMTVs in human breast cancer remains questionable. Yet a retroviral etiology of human breast cancer cannot be discarded since retroviruses are good candidates to play a role in diseases which, like human breast cancer, appear either as sporadic or inherited. Due to their replication cycle, retroviruses can be propagated not only as infectious agents able to freely infect host cells, but also as cellular genes which can be passed on to progeny. It is suggested here to search for a new human retrovirus in sporadic breast cancer, using the techniques which led to the isolation of human T-cell leukemia virus-1 (HTLV-1). Indeed, finding an infectious retrovirus in sporadic cases could lead, via the c-DNA probes derived from it, to testing the hypothesis that the inherited form of human breast cancer may result from the action of retroviral genes integrated in the germ line.

BRCA1 and BRCA2 in breast cancer

Breast cancer, one of the most common serious malignancies affecting women, occurs in hereditary and sporadic forms. Hereditary breast cancer accounts for 5-10% of all cases and has some distinctive clinical features compared with sporadic breast cancer. The recently identified genes BRCA1 and BRCA2 appear to account for the majority of hereditary breast cancer in US and European populations. Both of these genes have already been localized and isolated; however, the exact functions of their proteins are not clear yet. The detection of LOH in the 17q21 and 13q12-q13 regions, where the BRCA1 and BRCA2 genes are located, indicates that BRCA1 and BRCA2 act as tumor suppressor genes. The list of identified germline mutations in BRCA1 and BRCA2 is still growing, and mutation carriers have a substantial lifetime risk of both breast and ovarian cancer. However, it is still undetermined whether BRCA1 and BRCA2 play similar important roles in sporadic breast cancer. This paper reviews the current advances in BRCA1/BRCA2 research: the structure of their genes and proteins, their mutation frequencies, their possible roles in both hereditary and sporadic breast cancers, and their functions in transcriptional regulation and DNA repair.

Selective killing of preneoplastic and neoplastic cells by methotrexate with leucovorin

Three sublines of NIH 3T3 cells had the properties of non-neoplastic, preneoplastic, and neoplastic cells, respectively. The closer the cells were to neoplastic behavior, characterized by continuing growth at high density, the slower they multiplied at lower density. Under the conditions of high population density and low calf serum concentration used in the assay for transformed focus formation, the transformed or neoplastic cells were much more sensitive to killing by methotrexate (MTX) than were non-neoplastic cells in the same culture. This differential sensitivity of neoplastic cells was far more pronounced in molecular, cellular, and developmental biology medium 402 (MCDB 402) than in DMEM. It is associated with the presence in MCDB 402 of folinic acid, known clinically as leucovorin, which is a reduced form of the folic acid present in DMEM. Although leucovorin had been shown to selectively spare normal bone marrow and intestine in animals from the killing effect of MTX on tumor cells, we demonstrate the preferential killing of neoplastic over non-neoplastic cells of the same derivation. Neither neoplastic nor non-neoplastic cells were killed once they had stopped multiplying at their respective saturation densities. The development of the light foci characteristic of the preneoplastic cells was less sensitive to MTX than the formation of the dense foci produced by the fully neoplastic cells. The system should serve as a valuable model to establish basic principles and optimal conditions for selective killing of neoplastic cells by chemotherapeutic drugs.

Mutation screening of BRCA1 using PTT and LOH analysis at 17q21 in breast carcinomas from familial and non-familial cases

Germline mutations in the BRCA1 gene predispose to breast and ovarian cancer. An estimated 45% of families with multiple breast cancer cases and more than 80% of breast-ovarian cancer families are linked to BRCA1. Mutation analyses by collaborative laboratories have revealed around 460 distinct BRCA1 sequence alterations, mostly germline mutations from familial cases. The majority of these alterations were nonsense and frame-shift mutations. In the present study, breast tumors of both sporadic and familial origin were investigated for allelic imbalance (AI) at the BRCA1 locus. AI was observed in 52% of the sporadic cases and in 17% of the familial cases. Furthermore, 104 breast carcinomas from patients with sporadic disease and 77 patients with positive family histories of breast and/or ovarian cancer were examined for translation-terminating mutations in exon 11 of the BRCA1 gene using the protein truncation test (PTT). No somatic mutations were detected in any of the tumors analysed, and only one BRCA1 mutation carrier was found among the familial cases. The result of this study gives no indication that truncating somatic mutations in exon 11 of BRCA1 play a major role in the tumorigenesis of the breast. Furthermore, the frequency of such mutation carriers in breast cancer populations with weak family histories of breast and/or ovarian cancer seems to be low.

A review on family history of breast cancer: screening and counseling proposals for women with familial (non-hereditary) breast cancer

With the aim to specify screening recommendations for women with familial (non-hereditary) breast cancer (FBC) we analysed 59 studies using quantitative methods of pooling. The pooled relative risk (RR) and cumulative probability were used to estimate breast cancer risk. The RRs for women with a family history of breast cancer in a first-degree relative was 2.03 (95% CI 1.09-2.22). The highest RR is observed for women with a family history and atypical hyperplasia in their breast biopsy specimen (RR = 10.87, 95% CI 6.05-19.69). A high cumulative probability before the age of 50 was only found for women with a combination of two risk factors: a family history and atypical hyperplasia, namely 19% (95% CI 11-33%). The cumulative probabilities of women aged 50 to 70 years who have a family history were between 11% (95% CI 9-13%, a family history in combination with age at first birth before 22 years) and 53% (95% CI 35-75%, a family history in combination with atypical hyperplasia). These high risks suggest that women over 50 years of age who have a family history of FBC have to be actively encouraged to participate in a screening program consisting of a biannual palpation by a specialist, an annual mammogram and a monthly self-control. Yearly screening is recommended for women under 50 years of age who have a family history and atypical hyperplasia. These recommendations remain valid until the effectiveness of such screening programs is assessed.

Family history in ovarian cancer referral population

In order to determine the incidence of familial and hereditary ovarian cancer in a referral patient population, we conducted a retrospective study of 44 patients from a consecutive set of 62 patients treated for ovarian carcinoma at the Gynecologic Oncology Clinic at the Richland Memorial Hospital Center for Cancer Treatment and Research between January 1, 1993 and December 31, 1993. In our study of the referred patients, only two (4.55%) reported a history of at least one first-degree relative also being affected with ovarian cancer. However, 13 patients (29.55%) reported a family history consistent with one of the hereditary ovarian cancer syndromes. In addition to having a suggestive family history, these 13 families demonstrated several cardinal features of hereditary cancer syndromes including early onset, bilaterality, multiple primary tumors, and transmission. Race was the only significantly different demographic factor between the hereditary and sporadic ovarian cancer groups. All 13 patients who appeared to have a hereditary form of cancer were Caucasian.

MMTV-induced mutations in mouse mammary tumors: their potential relevance to human breast cancer

In mouse mammary tumor virus (MMTV) infected mice, three identifiable stages of mammary tumorigenesis can be biologically defined: preneoplastic hyperplastic nodules, malignant tumor, and distant metastatic lesions (primarily in the lung). MMTV is a biological carcinogen which induces somatic mutations as consequence of its integration into the host cellular genome. Each stage of mammary tumorigenesis appears to result from the clonal outgrowth of cells containing additional integrated proviral MMTV genomes. This phenomenon has provided the basis for an approach to identify genes which, when affected, may contribute to progression through the different stages of mammary tumorigenesis. Eight different genes (Wnt1, Wnt3, Wnt10b, Fgf3, Fgf4, Fgf8, Int3, and Int6) have been shown to be genetically altered in multiple mammary tumors as a consequence of MMTV integration. Although the significance of the human homologs of these genes as targets for somatic mutation during human breast carcinogenesis is only now being explored, it is clear that this work has led to a new appreciation of the complexity of the genetic circuitry that is involved in the control of normal mammary gland growth and development. It seems likely that some of the mutations induced by MMTV, and the signaling pathways in which these target genes take part, will be relevant to the progression from preneoplastic lesions to distant metastasis in human breast cancer.

Genetic heterogeneity in breast cancer susceptibility

Approximately 20% of breast cancer patients have a family history of the disease, and in one-fourth of these cases breast cancer appears to be inherited as an autosomally dominant trait. Five genes and gene regions involved in breast cancer susceptibility have been uncovered. Germ-line mutations in the recently cloned BRCA1 gene at 17q21 is considered to be responsible for the disease in a majority of the breast-ovarian cancer families and in 40-45% of the site-specific breast cancer families, but appears not to be involved in families with both male and female breast cancer cases. The BRCA2 locus at 13q12-q13 appears to be involved in 40-45% of the site-specific breast cancer families, and in most of the families with affected males. The gene located in this region, however, does not seem to confer susceptibility to ovarian cancer. The TP53 gene is involved in breast cancer development in the Li-Fraumeni syndrome and Li-Fraumeni syndrom-like families, whereas germ-line mutations in the androgen receptor (AR) gene is present in a subset of male breast cancers. Furthermore, females who are obligate carriers of ataxia telangiectasia (AT) have a 4-12 times relative risk of developing breast cancer as compared with the general female population, indicating that germ-line mutations in AT also confer susceptibility to breast cancer.

Familial clustering of obesity and breast cancer

One of the most striking characteristics of breast cancer (BC) is a tendency to familial aggregation. In order to evaluate whether familial clustering of obesity could account, at least in part, for the familial aggregation of BC, we compared the adult body size of entire sets of first-degree relatives belonging to 60 families with two or more cases of BC (case families) and 120 BC-free families (control families). Case families included an index case recently admitted for primary BC who had a confirmed first-degree family history for the disease. Control families included one population-based healthy index control with no family history and age-matched (2:1) to index cases. Index cases and controls, recruited from a pool of participants in a large case-control study, completed a questionnaire covering their own body size history as well as that of each of their first-degree relatives (598 case and 1,128 control relatives) using a validated system of body silhouette drawings. The odds ratio (OR) for premenopausal familial BC associated with having one parent markedly obese compared to none was 0.17 (95% confidence interval [CI] 0.04-0.65), while having both parents obese resulted in an OR of 0.25 (95% CI 0.04-1.56). Obesity among siblings was not related to premenopausal familial BC risk nor was familial obesity a significant predictor of familial BC after menopause. Index cases from both menopausal groups tended to be thinner than their unaffected relatives at age 40 years and thereafter. The inverse relationship between parental obesity and premenopausal BC risk is concordant with the protective effect of obesity on early-onset BC previously reported at the individual level.

Incidence of germ-line p53 mutations in patients with gliomas

Epidemiological studies on intracranial tumors have suggested that the observed familial aggregation of a proportion of gliomas may be due to inherited predisposition to their development. In the Li-Fraumeni syndrome (LFS) associated with germ-line mutations of the p53 gene, nervous-system tumors are observed with increased frequency. However, the contribution of germ-line p53 mutation to the incidence of brain tumors has not been investigated. In order to address this point, we have performed 2 independent investigations. First, we have examined an unselected series of brain tumors. Whenever the presence of a p53 mutation in the tumor was observed, the possible germ-line origin of the mutation was investigated. Germ-line p53 mutations were also analyzed in constitutional DNA of patients with gliomas that had been selected for an unusual personal or familial history of cancer. Germ-line p53 mutations were detected in 1 out of 80 unselected cases and in 3 out of 15 selected cases (20%). We conclude that germ-line p53 mutation may contribute to a small fraction of gliomas that develop in the general population. The presence of a personal or familial history of cancer in a patient with glioma should prompt the search for a germ-line p53 mutation. However, the low frequency of p53 germ-line mutation suggests that alterations of this gene may not account for most familial cases of gliomas.

Oestrogen receptor (ESR) polymorphisms and breast cancer susceptibility

The allele frequencies of three restriction fragment length polymorphisms at the oestrogen receptor (ESR) locus were compared between breast cancer patients and controls. Leucocyte or tumour DNA from 238 and 122 patients, respectively, and leucocyte DNA from 672 controls was analysed. Alleles having the XbaI restriction site detected by the M72 probe (covering exon 2 and flanking introns) were significantly more frequent in patients than in controls (P = 0.033). Within the breast cancer population, the presence of the XbaI restriction site was associated with late onset of the disease but this association was only of borderline significance. The allele frequencies of the BstUI polymorphism in exon 1 and the PvuII polymorphism in intron 1 did not differ between cases and controls. However, alleles with the PvuII restriction site were more frequent in patients with progesterone receptor negative primary tumours than in patients with progesterone receptor positive primary tumours (P = 0.027). There was no significant association between any of the ESR polymorphisms and the oestrogen receptor status of the primary tumours. The results indicate that the ESR gene or a gene closely linked to it is involved in the development of at least a subset of breast carcinomas.

Prevalence of aneuploidy, overexpressed ER, and overexpressed EGFR in random breast aspirates of women at high and low risk for breast cancer

Breast tissue biomarkers which accurately predict breast cancer development within a 10 year period in high risk women are needed but currently not available. We initiated this study to determine 1) the prevalence of one or more breast tissue abnormalities in a group of women at high risk for breast cancer, and 2) if the prevalence of biomarker abnormalities is greater in high risk than in low risk women. Eligible high risk women were those with a first degree relative with breast cancer, prior breast cancer, or precancerous mastopathy. Low risk women were those without these or other major identifiable risk factors. Ductal cells were obtained via random fine needle aspirations and cytologically classified. Biomarkers included DNA ploidy, estrogen receptor (ER), and epidermal growth factor receptor (EGFR). The prevalence of DNA aneuploidy was 30%, overexpression of ER 10%, and overexpression of EGFR 35%, in the 206 high risk women whose median 10 year Gail risk (projected probability) of developing breast cancer was 4.5%. The prevalence of aneuploidy and overexpressed EGFR was significantly higher in the high risk women than in the 25 low risk controls (p < 0.002), whose median 10 year Gail risk was 0.7%. The difference in the prevalence of ER overexpression between high and low risk groups was not statistically significant (p = 0.095). This may be due to the low prevalence of overexpressed ER and the small number of controls. A significant difference was noted in the prevalence of one or more abnormal biomarkers between the high risk and low risk women (p < 0.001). A large prospective trial is needed to determine if one or more of these biomarkers, is predictive of breast cancer development.

c-myc oncogene expression: a marker for females at risk of breast carcinoma

In an attempt to identify patients at risk of breast cancer, 9E 10 c-myc monoclonal antibody was used to detect the oncogene products in 64 breast tissue biopsies. There were 44 specimens of benign breast disorders: 21 from patients who developed subsequent breast cancer, and 23 from patients who did not. The remainder were malignant tumor biopsies from those who developed breast cancer. C-myc over-expression was identified in 12 (60%) of the breast carcinomas; it was also noted in 13 (62%) of the benign biopsies from patients who developed subsequent breast carcinoma. Expression was observed in only 3 (13%) controls--patients who did not develop cancer. A prospective study is now warranted to determine the clinical usefulness of our findings.

Genetic and molecular heterogeneity of breast cancer cells

We have undertaken a systematic study of primary human breast tumor DNAs to identify and characterize frequently occurring somatic mutations. Loss of heterozygosity (LOH) was found on chromosomes 1p (37%), 1q (20%), 3p (30%), 7 (41%), 13q (30%), 17p (49%), 17q (29%) and 18q (34%) in our tumor DNA panel. Specific subsets of tumors could be defined based on the particular collection of mutations they contained. One goal of these studies has been to determine whether there is a significant association between specific mutations and clinical parameters of the disease. We have found that LOH on chromosome 17p in tumor DNAs is associated with breast tumors having a high proliferative index and that LOH on chromosome 7 is associated with patients having a poor prognosis. Our analysis of chromosome 17 suggests that there may be as many as four tumor suppressor genes affected in primary human breast tumors.

Definition of regions of the human genome affected by loss of heterozygosity in primary human breast tumors

We have undertaken a systematic study of primary human breast tumor DNA to identify and characterize frequently occurring somatic mutations. Loss of heterozygosity (LOH) has been the most frequent mutation in our panels of primary breast tumor DNA. It is currently thought that LOH reveals recessive mutations within the affected region of the genome. One goal of our studies has been to physically define the target genes revealed by LOH in primary breast tumors. We have focused our efforts on chromosome 17, finding five regions of the chromosome which are independently affected by LOH in breast tumors. Two apparent target loci are on chromosome 17p; one is the TP53 gene. The other is an as-yet undefined locus telomeric to the TP53 gene. Loss of expression of the nme1 gene on chromosome 17q in tumors was linked to patients with a poor prognosis (p = 0.018). Although a significant trend (p = 0.05) was found between LOH of the nme1 gene and loss of nme1 expression, no point mutations were found within the coding region of the nme1 gene by single strand conformational polymorphism (SSCP) or nucleotide sequence analysis. These and other results suggest to us that there may be potential tumor suppressor genes both centromeric and telomeric to the nme1 locus on chromosome 17q.

Clinical heterogeneity of hereditary breast cancer and its impact on screening protocols: the Dutch experience on 24 families under surveillance

We investigated 24 families who satisfied a set of criteria for hereditary breast cancer. Five families had only breast cancer, four a combination of breast and ovarian cancer and the remaining 15 had also a variety of other cancers. The families include 86 patients, 78 of which had a malignant tumour and the rest had a benign lesion in the breast. The median age at diagnosis of the breast cancer was 47 years. Three of the 24 families were of a late onset variant. 58 of the 86 patients were symptomatic while 18 were identified during presymptomatic screening because of a positive family history. In 10 cases the reason for referral was not known. 56 of the symptomatic patients had a malignant breast lesion, 52% of which were with lymph node metastasis whereas 12 of the screening group had breast cancer with 2 patients showing lymph node involvement (P = 0.06). 22 of the symptomatic patients and none of the screening patients died of breast cancer after a median observation period of 6 and 7 years, respectively (P < 0.05).

Genetic alterations of the tumour suppressor gene regions 3p, 11p, 13q, 17p, and 17q in human breast carcinomas

Fifty-nine primary breast carcinomas and 11 metastases were examined to identify genetic alterations in the tumour suppressor gene regions 3p, 11p, 13q, 17p, and 17q. Loss of heterozygosity (LOH) was frequently observed on chromosome arms 17p (p144D6 lost in 75%, pYNZ22.1 in 55%, and TP53 in 48% of the primary tumours), 13q (RBI lost in 40% of the primary tumours), and 17q (pRMU3 lost in 35%, pTHH59 in 29%, and NM23HI in 26% of the primary tumours). Loss of all the markers except p144D6 was observed even more frequently in the metastases. Pairwise comparisons for concordance of allele losses on 17p indicated that there might be two genes on 17p implicated in breast cancer development; the TP53 gene and a gene located close to the p144D6 and pYNZ22.1 markers. LOH of the RBI gene was associated with LOH of pYNZ22.1 and p144D6, but not with LOH of TP53. LOH of RBI and TP53 was associated with occurrence of ductal carcinomas, RBI and p144D6 losses with tumour size, and p144D6 losses with positive node status as well. LOH of TP53 and the three 17q markers NM23HI, pTHH59, and pRMU3 was most frequently observed in tumours from postmenopausal women. p144D6 losses occurred most frequently in progesterone receptor-negative tumours, whereas pTHH59 losses occurred most frequently in oestrogen receptor-negative tumours. LOH of the investigated loci was not associated with ERBB2 protooncogene amplification, with positive family history of breast cancer, or with survival.

Breast carcinoma and skeletal formation

We have studied skeletal structure in 67 women with breast carcinoma and in 59 women without breast carcinoma, looking for differences of development that might be correlated with hormonal, metabolic or genetic abnormalities. We have measured the lengths of the limbs and of their segments (upper arm, forearm, thigh, leg), of the bisacromial and bitrochanteric transverse diameters and total height and height divided into the parts from vertex to pubis and from pubis to the ground. The analysis showed statistically significant coefficients of regression with presence of mammary carcinoma for height (0.0904262, S.D. 0.0461), length of thigh (0.12989, S.D. 0.03981) and length of lower leg (-0.68475, S.D. 0.1390). This skeletal type might be the expression of a genetic condition that is associated with the existence of mechanisms that permit development of mammary cancer.

Somatic mutations and human breast cancer. A status report

A systematic study of primary human breast tumor DNA demonstrated that three proto-oncogenes or regions of the genome (c-myc, int-2, and c-erbB2) are frequently amplified and that there is loss of heterozygosity (LOH) on chromosomes 1p(37%), 1q(20%), 3p(30%), 7(41%), 11p(20%), 13q(30%), 17p(49%), 17q(29%), and 18q(34%). Specific subsets of tumors can be defined based on the particular collection of mutations they contain. For instance, LOH on chromosomes 11p, 17p, and 18q frequently occurs in the same tumor. A search for putative tumor suppressor genes within the regions of the genome affected by LOH has been started. In a comprehensive molecular analysis of the p53 gene on chromosome 17p, 46% of the tumors contained a point mutation in the p53 gene.

Management of the high-risk patient

While breast cancer is affecting American women at an epidemic rate, certain patients are identified as being at particularly high risk because of environmental, endocrine, genetic, and pathologic risk factors. Risk assessment, dietary, and psychological counseling, as well as breast cancer screening, are the function of a high-risk breast cancer program. Our own program is discussed.

Cytogenetic features of twenty-six primary breast cancers

Tumor preparations from 26 primary breast cancers were studied cytogenetically with G-banding, using a direct technique, synchronized short-term culture, or both. Two tumors had normal karyotypes, and 24 (92%) had chromosomal abnormalities. Nineteen tumors had chromosome 1 rearrangements, with 10 cases (40%) displaying distal short arm translocations (1p36). Other frequent breakpoints occurred at 3p21, 6q22-27, 11q21-25, 16q22-24, 17p, and 19q13. To seek primary rather than secondary cytogenetic changes, attention was directed toward tumors with diploid-range karyotypes (32-57 chromosomes per cell). Of four such tumors, three exhibited nonrandom involvement of chromosome 16q22. This, together with previously reported data, suggests that deletion or rearrangement of chromosome 16q21-24 may be a primary or specific event in a subset of breast cancers.

Is aryl hydrocarbon hydroxylase activity a new prognostic indicator for breast cancer?

Aryl hydrocarbon hydroxylase (AHH) activity was measured in the breast tumours of 153 primary and 17 recurrent cancer patients, and in 18 patients with benign breast tumour. All operations were carried out in 1983-84. The cytosolic fraction was collected for steroid receptor determination, and microsomes were separated for AHH assay from the same tissue samples. The AHH distribution was wide and highly skewed in all groups. About 10% of the samples showed activities below detection limit. The medians and ranges for primary cancers were 34 (less than 5-2683), for recurrent cancers 40 (20-239) and for benign tumours 11 (less than 5-37) fmol min-1 mg-1 protein. After logarithmic transformation, the mean AHH activities of cancer samples differed significantly from those of benign tumours. The logarithm of AHH activity (log AHH) correlates positively with axillary lymph node status, and negatively with steroid receptor levels. The development of the disease and the survival of the patients were followed for 4 years. The survival and the disease-free interval of the cancer patients who had low AHH activity was significantly higher than that of the high AHH group. The multivariate analysis with Cox's proportional hazad model showed primary tumour size, progesterone receptor concentration, nodal status and log AHH to be the most important independent prognostic factors for survival, while the occurrence of metastases, log AHH and tumour size were the equivalent factors for the disease-free interval in primary breast cancers. We conclude that AHH activity may reflect the overall malignant potential of breast cancer tissue.

Familial occurrence of gastric cancer in the 2-year experience of a population-based registry

The authors studied the familial occurrence of tumors in 154 individuals with gastric cancer by reviewing the clinical data and the genealogical tree of all patients registered in 1986 through 1987 in the Local Health Care District of Modena, Italy, for cancer of the stomach. Crude and age-adjusted (world population) incidence rates of gastric cancer were 34.0 and 21.4 new cases/100,000/year, respectively, in men, and 24.5 and 10.9 in women, respectively. Among first-degree relatives of the registered patients there were 30 cases of gastric carcinoma versus 15 cases in a control group matched for age and sex (Mantel-Haenszel odds ratio [M-H OR] 3.14, P less than 0.01). This excess of gastric neoplasms was observed in siblings (17 versus 7, M-H OR 4.33, P less than 0.02) but not in parents (13 versus 8, not significant). Besides gastric cancer, there was no significant excess of other type of tumors in case families. The familial occurrence of gastric cancer tended to be more frequent in patients with "diffuse" carcinoma (52%) than in subjects with "intestinal" cancer (33%), although the difference was not statistically significant. In conclusion, the current investigation suggests that a "family history" for gastric neoplasms is usually observed in approximately 10% to 15% of the registered cases. As already described for other common malignancies, therefore, the familial occurrence of gastric carcinoma suggests the existence of a genetic susceptibility to cancer of the stomach, at least in a fraction of these patients.

Mammographic screening of women with increased risk of breast cancer

Five hundred one women from Dallas County, Texas who participated in the American Cancer Society 1987 Texas Breast Screening Project were selected because of a self-reported family history of breast cancer (cases). They were matched with 501 randomly selected women from the same county with no family history (controls). Although there was a statistically significant trend with age for an increasing proportion of women to report having undergone mammography, there was no significant difference when comparing mammographic histories of cases with controls after controlling for age (31.5% versus 35.1%, P = 0.33). Significantly more cases (79%) perceived their risk for breast cancer to be moderate or greater compared with controls (54%, P less than 0.0001), but mammographic histories were not different when controlling for perceived risk. Both cases and controls cited lack of physician referral and cost as their reasons for not having undergone mammography. Women at increased risk for breast cancer (because of their family history) are not undergoing regular mammographic screening despite their self-awareness of the increase in their risk.

What can a woman do about her risk of dying of breast cancer?

Every day, American women are told that one in ten will develop breast cancer, and some groups perceive their risk to be so high as to justify immediate bilateral mastectomy. Many associations with breast cancer have been identified, including a history of benign breast diseases, in situ carcinoma, a family history of breast cancer, prolonged menstruation as a result of early menarche or delayed menopause, few or late pregnancies, excessive alcohol intake, obesity, and possibly the use of estrogens as oral contraceptives or postmenopausal replacement therapy. In spite of these associations, our understanding of either the cause(s) of breast cancer or the sequence of events leading to a diagnosis of breast cancer is still inadequate to make global public health recommendations regarding life style--or even to initiate well-designed studies. The epidemiologic evidence strongly suggests, however, that events relatively early in a woman's life are more important than later events, even though most of the risk of developing breast cancer will be expressed after the age of 75. Possibly one of the greatest contributions we can make to our patients' welfare is to share the knowledge that the risk of dying of breast cancer is considerably smaller than the risk of developing breast cancer; that the risk of early death from breast cancer rarely exceeds 10% in even the highest risk groups; and that the life styles most likely to reduce the risk of cardiovascular disease and other scourges of womankind are also those most likely to reduce the risk of developing breast cancer.

Breast cancer cytogenetics and beyond

It is hypothesized that cancers arise as a result of genetic or chromosomal alteration. Evidence for this is provided by the leukaemias and lymphomas in which cytogenetic studies are of established value in diagnosis, classification and follow-up. In contrast, the cytogenetic study of all solid tumours, including breast carcinoma, is in its infancy. However, cytogenetic studies indicate that clonal structural alterations do occur, affecting several loci on a number of chromosomes. Molecular studies provide further evidence of recurring chromosomal breakpoints in breast cancer. This paper reviews the chromosomal rearrangements observed to date and discusses their relevance to the biology of breast cancer.