Numerous high-risk epithelial lesions in familial breast cancer

Ductal Carcinoma In Situ (DCIS) Diagnosed by MRI-Guided Biopsy among BRCA1/BRCA2 Mutation Carriers

Background

While BRCA1/BRCA2 pathogenic sequence variants (PSVs) clearly confer an increased risk for invasive breast cancer, the extent to which these mutant alleles increase DCIS risk is less clear.

Objective

To assess the rate of detection over a 5-year period, and MRI imaging features of pure noncalcified DCIS in a cohort of Israeli BRCA1/BRCA2 PSV carriers attending a high-risk clinic from 2015 to 2020.

Materials and Methods

All female BRCA1/BRCA2 PSV-carriers followed at the Meirav High-risk clinic from 2015 to 2020 were eligible if they underwent semiannual breast imaging (MRI/mammography) and MRI-guided biopsy-proven pure DCIS. Clinical data, pathology information, and imaging characteristics were retrieved from the computerized archiving system.

Results

18/121 (15.2%) participating BRCA1 PSV carriers and 8/81 (10.1%) BRCA2 PSV-carriers who underwent MRI-guided biopsy were diagnosed with DCIS. The median age of BRCA1 carriers and BRCA2 carriers was 49.8 years and 60.6 years, respectively (p = 0.55). Negative estrogen-receptor tumors were diagnosed in 13/18 (72%) BRCA1 and 2/8 (25%) BRCA2 PSV carriers (p < 0.05). Thirteen (13/18–72%) BRCA1 carriers had intermediate to high-grade or high-grade DCIS compared with 4/8 (50%) of BRCA2 carriers (p = 0.03). Over the 5-year study period, 29/1100 (2.6%) BRCA1/BRCA2 PSV carriers were diagnosed with DCIS seen on MRI only.

Conclusion

MRI-detected noncalcified DCIS is more frequent in BRCA1 PSV carriers compared with BRCA2 carriers, unlike the BRCA2 predominance in mammography-detected calcified DCIS. BRCA1-related DCIS is diagnosed earlier, more likely to be estrogen receptor-negative and of higher grade compared with BRCA2-related DCIS. Future prospective studies should validate these results and assess the actual impact they might have on clinical management of BRCA PSV carriers.

Non-BRCA familial breast cancer: review of reported pathology and molecular findings

The majority of women evaluated for a clinical concern of possible hereditary breast cancer syndromes have no identified pathogenic variants in genes predisposing them to breast cancer. Non-BRCA1- or BRCA2-related familial breast cancer, also called 'BRCAX', thus comprises a sizeable proportion of familial breast cancer but it is poorly understood. In this study, we reviewed 14 studies on histopathology and molecular studies of BRCAX to determine if there were differences between 'sporadic' breast cancers and compared to cancers arising in women harbouring variants in known cancer predisposition genes. Across available literature, there was inconsistency on inclusion and exclusion criteria, reported parameters, and use of controls. Cohorts were small, and while several studies reported findings that appeared to distinguish the BRCAX cases from sporadic and/or gene-positive controls, no findings were reported in more than one study. To determine whether the BRCAX families might still contain important genetic subsets awaiting discovery will require prospective ascertainment of a large number of women with familial breast cancer who are screened for all currently established predisposition genes, whose tumours are assessed for multiple parameters in a uniform manner, and in which controls (BRCA1/2+ and non-familial 'sporadic' cases) are collected from the same population.

DCIS in BRCA1 and BRCA2 mutation carriers: prevalence, phenotype, and expression of oncodrivers C-MET and HER3

Background

Studies report conflicting evidence regarding the existence of a DCIS-associated premalignant pathway in BRCA mutation carriers. We aimed to examine the prevalence, phenotype, and expression of oncodrivers in pure DCIS (pDCIS) and invasive breast cancer with concurrent DCIS (IBC + DCIS) in mutation carriers.

Methods

A cohort of BRCA1 and BRCA2 mutation carriers >18 years old who underwent surgery for breast cancer at an academic hospital (1992–2011) and had pathology available for review were included for study. Invasive breast cancer (IBC) and DCIS were stained for ER, PR, HER1, HER2, and HER3, and C-MET. DCIS prevalence was evaluated. Correlation of IBC and DCIS phenotypes was evaluated in patients with IBC + DCIS. DCIS and IBC expression of tumor markers were examined by BRCA mutation.

Results

We identified 114 breast tumors. Of all BRCA1-associated tumors, 21.1 % were pDCIS and 63.4 % were IBC + DCIS. Of all BRCA2-associated tumors, 23.3 % were pDCIS and 60.5 % were IBC + DCIS. In BRCA1 and BRCA2 mutation carriers with IBC + DCIS, there was a significant correlation in ER, PR, and HER3 expression between the DCIS and IBC components. Most BRCA1-associated DCIS did not express ER, PR or HER2, while most BRCA2-associated DCIS did express ER and PR. BRCA1− as well as BRCA2-associated DCIS had expression of HER3 and C-MET.

Conclusions

The majority of BRCA-associated tumors had DCIS present. Concordance of DCIS and IBC phenotypes was high, arguing for the existence of a DCIS-associated premalignant pathway. Oncodrivers HER3 and C-MET were expressed in the DCIS of mutation carriers, suggesting an opportunity for prevention strategies.

Risk reducing mastectomy, breast reconstruction and patient satisfaction in Norwegian BRCA1/2 mutation carriers

The aim of this study was to evaluate the outcome of risk-reducing mastectomy in BRCA1/2 mutation carriers with and without breast cancer. Uptake, methods of operation and reconstruction, complications, patient satisfaction and histopathological findings were registered at all five departments of genetics in Norway. Data from 267 affected and unaffected BRCA1/2 mutation carriers were analyzed, including a study-specific questionnaire returned by 178 mutation carriers. There was a steady increase in the uptake of risk-reducing mastectomies during the study period. Complications were observed in 106/266 (39.7%) women. Patient satisfaction was high. The majority of women expressed great relief after risk-reducing mastectomy and would have chosen the same option again.

HIF-1α overexpression in ductal carcinoma in situ of the breast in BRCA1 and BRCA2 mutation carriers

Recent studies have revealed that BRCA1 and BRCA2 germline mutation-related breast cancers show frequent overexpression of hypoxia inducible factor-1α (HIF-1α), the key regulator of the hypoxia response. However, the question remained whether hypoxia is a late stage bystander or a true carcinogenetic event in patients with hereditary predisposition. We therefore studied HIF-1α overexpression in ductal carcinoma in situ (DCIS), an established precursor of invasive breast cancer.

We used immunohistochemistry to examine the expression of the hypoxia markers HIF-1α, CAIX and Glut-1 in DCIS and available invasive carcinoma lesions of 32 BRCA1, 16 BRCA2 and 77 non-BRCA mutation-related cases. HIF-1α expression was detected in 63% of BRCA1 and 62% of BRCA2 as compared to 34% of non-BRCA mutation-related DCIS cases (p = 0.005). CAIX overexpression was present in 56% of BRCA1 and 44% of BRCA2 as compared to 6% of non-BRCA mutation-related DCIS cases (p = 0.000). Glut-1 overexpression was observed in 59% of BRCA1, 75% of BRCA2 and 67% of non-BRCA mutation-related DCIS cases (p = 0.527). Overall, HIF-1α, CAIX and Glut-1 expression in BRCA mutation-related DCIS matched the expression in the accompanying invasive cancers in 60% or more of cases. In non-BRCA mutation-related cases the expression of the hypoxia markers in DCIS matched the expression in the invasive part in 46% or more of the cases.

Although BRCA1 and BRCA2 germline mutation-related invasive breast cancers are different in many ways, the hypoxia-related proteins HIF-1α, CAIX and Glut-1 are expressed in both DCIS and invasive lesions of BRCA1 and BRCA2 mutation carriers. This suggests that hypoxia may already play a role in the DCIS stage of BRCA1 and BRCA2 germline mutation related breast carcinogenesis, and may also drive cancer progression. Hypoxia-related proteins are therefore putative targets for therapy and molecular imaging for early detection and monitoring therapy response in BRCA mutation patients.

Pathology of hereditary breast cancer

Background

Hereditary breast cancer runs in families where several members in different generations are affected. Most of these breast cancers are caused by mutations in the high penetrance genes BRCA1 and BRCA2 accounting for about 5% of all breast cancers. Other genes that include CHEK2, PTEN, TP53, ATM, STK11/LKB1, CDH1, NBS1, RAD50, BRIP1 and PALB2 have been described to be high or moderate penetrance breast cancer susceptibility genes, all contributing to the hereditary breast cancer spectrum. However, in still a part of familial hereditary breast cancers no relationship to any of these breast cancer susceptibility genes can be found. Research on new susceptibility genes is therefore ongoing.

Design

In this review we will describe the function of the today known high or moderate penetrance breast cancer susceptibility genes and the consequences of their mutated status. Furthermore, we will focus on the histology, the immunophenotype and genotype of breast cancers caused by mutations in BRCA1 and BRCA2 genes and the other high or moderate penetrance breast cancer susceptibility genes. Finally, an overview of the clinical implications of hereditary breast cancer patients will be provided.

Conclusion

This information leads to a better understanding of the morphological, immunohistochemical and molecular characteristics of different types of hereditary breast cancers. Further, these characteristics offer clues for diagnosis and new therapeutic approaches.

Molecular profile of ductal carcinoma in situ of the breast in BRCA1 and BRCA2 germline mutation carriers

Aims:

Ductal carcinoma in situ (DCIS) is an established late precursor of sporadic invasive breast cancer and to a large extent parallels its invasive counterpart with respect to molecular changes and immunophenotype. Invasive breast cancers in germline BRCA1 and BRCA2 mutation carriers have a distinct “basal” and “luminal” immunophenotype, respectively, but the immunophenotype of their precursor lesions has hardly been studied, and this was the aim of this study.

Methods:

DCIS lesions of 25 proven BRCA1 and 9 proven BRCA2 germline mutation carriers and their 22 and 6, respectively, accompanying invasive lesions were stained by immunohistochemistry for oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER)2/neu, cytokeratin (CK)5/6, CK14, epidermal growth factor receptor (EGFR) and Ki67.

Results:

DCIS lesions in BRCA1 mutation carriers were mostly of the basal molecular type with low ER/PR/HER2 expression, while they frequently expressed CK5/6, CK14 and EGFR, and were mostly grade 3 and highly proliferative. DCIS lesions in BRCA2 mutation carriers were mostly of luminal molecular type with frequent expression of ER/PR, and infrequent expression of CK5/6, CK14 and EGFR, and they were mostly grade 3 and showed low proliferation. In BRCA1 and BRCA2 mutation carriers there was a high concordance between DCIS lesions and their concomitant invasive counterpart with regard to expression of individual markers as well as “molecular” subtype.

Conclusions:

Although the number of cases studied was low, DCIS lesions in BRCA1 and BRCA2 mutations carriers are usually of the basal and luminal molecular type, respectively, similar to their accompanying invasive cancers, thereby providing evidence that DCIS is a direct precursor lesion in these hereditary predisposed patients. This also suggests that crucial carcinogenetic events leading to these phenotypes in hereditary predisposed patients occur before the stage of invasion.

Altered proliferation and differentiation properties of primary mammary epithelial cells from BRCA1 mutation carriers

Female BRCA1 mutation carriers have a nearly 80% probability of developing breast cancer during their life-time. We hypothesized that the breast epithelium at risk in BRCA1 mutation carriers harbors mammary epithelial cells (MEC) with altered proliferation and differentiation properties. Using a three-dimensional culture technique to grow MECs ex vivo, we found that the ability to form colonies, an indication of clonality, was restricted to the aldehyde dehydrogenase 1-positive fraction in MECs but not in HCC1937 BRCA1-mutant cancer cells. Primary MECs from BRCA1 mutation carriers (n = 9) had a 28% greater ability for clonal growth compared with normal controls (n = 6; P = 0.006), and their colonies were significantly larger. Colonies in controls and BRCA1 mutation carriers stained positive for BRCA1 by immunohistochemistry, and 79% of the examined single colonies from BRCA1 carriers retained heterozygosity for BRCA1 (ROH). Colonies from BRCA1 mutation carriers frequently showed high epidermal growth factor receptor (EGFR) expression (71% EGFR positive versus 44% in controls) and were negative for estrogen receptor (ERalpha; 32% ER negative, 44% mixed, 24% ER positive versus 90% ER positive in controls). Expression of CK14 and p63 were not significantly different. Microarray studies revealed that colonies from BRCA1-mutant PMECs anticipate expression profiles found in BRCA1-related tumors, and that the EGFR pathway is up-regulated. We conclude that BRCA1 haploinsufficiency leads to an increased ability for clonal growth and proliferation in the PMECs of BRCA1 mutation carriers, possibly as a result of EGFR pathway activation. These altered growth and differentiation properties may render BRCA1-mutant PMECs vulnerable to transformation and predispose to the development of ER-negative, EGFR-positive breast cancers.

High prevalence of preinvasive lesions adjacent to BRCA1/2-associated breast cancers

Mutations in BRCA1 and BRCA2 increase a woman's lifetime risk of developing breast cancer by 43% to 84%. It was originally postulated that BRCA1/2-associated breast cancers develop more rapidly than sporadic cancers and may lack preinvasive lesions. More recent studies have found preinvasive lesions in prophylactic mastectomy specimens from mutation carriers; however, there is little information on the presence of preinvasive lesions in tissue adjacent to breast cancers. Our aim is to investigate the role of preinvasive lesions in BRCA-associated breast carcinogenesis. We retrospectively compared BRCA1/2-associated breast cancers and sporadic breast cancers for the prevalence of preinvasive lesions [ductal carcinoma in situ (DCIS), lobular carcinoma in situ, and atypical lobular hyperplasia] in tissue adjacent to invasive breast cancers. Pathology was reviewed for 73 BRCA1/2-associated tumors from patients with breast cancer. We selected 146 patients with mutation-negative breast cancer as age-matched controls. Among the BRCA1/2-associated breast cancers, 59% had at least one associated preinvasive lesion compared with 75% of controls. Preinvasive lesions were more prevalent in BRCA2 mutation carriers than in BRCA1 mutation carriers (70% versus 52%, respectively). The most common preinvasive lesion in both groups was DCIS; 56% of BRCA1/2-associated breast cancers and 71% of the sporadic breast cancers had adjacent intraductal disease, respectively. Preinvasive lesions, most notably DCIS, are common in BRCA1/2-associated breast cancers. These findings suggest that BRCA1/2-associated breast cancers progress through the same intermediate steps as sporadic breast cancers, and that DCIS should be considered as a part of the BRCA1/2 tumor spectrum.

Tumor characteristics as an analytic tool for classifying genetic variants of uncertain clinical significance

It is important to identify a germline mutation in a patient with an inherited cancer syndrome to allow mutation carriers to be included in cancer surveillance programs, which have been proven to save lives. Many of the mutations identified result in premature termination of translation, and thus in loss-of-function of the encoded mutated protein. However, the significance of a large proportion of the sequence changes reported is unknown. Some of these variants will be associated with a high risk of cancer and have direct clinical consequence. Many criteria can be used to classify variants with unknown significance; most criteria are based on the characteristics of the amino acid change, on segregation data and appearance of the variant, on the presence of the variant in controls, or on functional assays. In inherited cancers, tumor characteristics can also be used to classify variants. It is worthwhile to examine the clinical, morphological and molecular features of a patient, and his or her family, when assessing whether the role of a variant is likely to be neutral or pathogenic. Here we describe the advantages and disadvantages of using the tumor characteristics of patients carrying germline variants of uncertain significance (VUS) in BRCA1, BRCA2, or in one of the mismatch repair (MMR) genes, MLH1, MSH2, or MSH6, to infer pathogenicity.

Histopathological findings and follow-up after prophylactic mastectomy and immediate breast reconstruction in 100 women from families with hereditary breast cancer

AIM

To survey the histopathological abnormalities in breasts of women who have undergone risk reducing mastectomy and to evaluate the effect of this measure on future breast cancer development.

PATIENTS/METHODS

Between August 1995 and October 2006 100 consecutive women with a hereditary increased risk of breast cancer underwent prophylactic mastectomy (PM) at Malmö University Hospital. Fifty of the 100 women had no previous breast cancer. Fifty were BRCA1 or BRCA2 mutation carriers. All breast specimens have been examined histopathologically according to a prospective protocol. Follow-up data was collected from medical records and data in the Regional Cancer Registry.

RESULTS

In the PM specimens abnormal lesions were found in 18 women (three with invasive cancers, eight in situ cancers and seven atypical hyperplasia). In previously healthy women lesions were more frequent after the age of 40 than among younger women (p=0.03). BRCA mutation carriers were more likely to present with ADH (atypical ductal hyperplasia)/ALH (atypical lobular hyperplasia) compared to the non-carriers/untested cases (p=0.01). After a median follow-up of 52 months (range 1-136 months) none of the women have developed breast cancer in the area of the prophylactically removed breast.

CONCLUSIONS

Prevalent atypical or malignant lesions are relatively a common finding in PM specimens in asymptomatic women with hereditary increased risk of breast cancer. Such findings were significantly more common above age 40 in women without previous breast cancer. The risk of newly formed breast cancer after PM is small. The clinical importance of detecting a premalignant or preinvasive lesion in the breast at PM is still unclear.

Frequency of Clinically Occult Intraepithelial and Invasive Neoplasia in Reduction Mammoplasty Specimens: A Study of 516 Cases

Reduction mammoplasty is a frequently performed procedure for the treatment of macromastia and for the achievement of symmetry in breast cancer patients following lumpectomy. Slides from 516 consecutive bilateral reduction mammoplasties performed for macromastia over 15 years were reviewed. Among these, 92 (18%) low-risk ductal intraepithelial neoplasia/intraductal hyperplasia, 28 (5%) ductal intraepithelial neoplasia 1 (1 low-grade ductal carcinoma in situ, 11 atypical intraductal hyperplasia, and 16 flat type), 17 (3%) lobular intraepithelial neoplasia, and 1 (0.2%) tubular carcinoma were identified. The patients were categorized into 3 age groups: <40 (n = 352), 40 to 50 (n = 107), and over 50 years (n = 57); the frequency of the lesions increased with age. These data confirm the low frequency of clinically occult malignancies identified in reduction mammoplasty specimens and provide substantial information about the frequency of a variety of intraepithelial proliferations. Preoperative mammography, specimen orientation, and inking of margins with 1 color are advised when reduction mammoplasty is scheduled for women ≥ 40 years of age.

Prophylactic mastectomy in familial breast carcinoma. What do the pathologic findings learn us?

OBJECTIVE

To evaluate the indications, techniques and pathologic findings of prophylactic mastectomy (pME).

METHODS

Retrospective study of patients with a strong family history of breast cancer (and ovarian cancer) or with proven BRCA mutation.

RESULTS

Between January 1995 and December 2005, sixty seven patients underwent pME: 15% had a BRCA1 mutation, 31% had a BRCA2 mutation and 33% had a strong family history but without proven BRCA mutation and in 21% mutation analysis was not performed. Fifty eight percent had a personal history of breast cancer of which 84% previously underwent a unilateral mastectomy as part of their treatment. The median time to decision from previous treatment for breast carcinoma to pME was 46 months. Mean age at pME was 43 years. Pathologic examination of the pME specimens revealed invasive and/or in situ carcinoma in 19% (13/67). Atypical ductal/lobular hyperplasia (ADH/ALH) or flat epithelial atypia (FEA) were present in another 3%.

CONCLUSION

Twenty two percent of women at high risk for breast cancer presented at the time of pME with invasive carcinoma or intra-epithelial neoplasia undetected by imaging and clinical examination.