Tumour spectrum in non-BRCA hereditary breast cancer families in Sweden

A Swedish Familial Genome-Wide Haplotype Analysis Identified Five Novel Breast Cancer Susceptibility Loci on 9p24.3, 11q22.3, 15q11.2, 16q24.1 and Xq21.31

Most breast cancer heritability is unexplained. We hypothesized that analysis of unrelated familial cases in a GWAS context could enable the identification of novel susceptibility loci. In order to examine the association of a haplotype with breast cancer risk, we performed a genome-wide haplotype association study using a sliding window analysis of window sizes 1-25 SNPs in 650 familial invasive breast cancer cases and 5021 controls. We identified five novel risk loci on 9p24.3 (OR 3.4; p 4.9 × 10^-11), 11q22.3 (OR 2.4; p 5.2 × 10^-9), 15q11.2 (OR 3.6; p 2.3 × 10^-8), 16q24.1 (OR 3; p 3 × 10^-8) and Xq21.31 (OR 3.3; p 1.7 × 10^-8) and confirmed three well-known loci on 10q25.13, 11q13.3, and 16q12.1. In total, 1593 significant risk haplotypes and 39 risk SNPs were distributed on the eight loci. In comparison with unselected breast cancer cases from a previous study, the OR was increased in the familial analysis in all eight loci. Analyzing familial cancer cases and controls enabled the identification of novel breast cancer susceptibility loci.

A Swedish Genome-Wide Haplotype Association Analysis Identifies a Novel Breast Cancer Susceptibility Locus in 8p21.2 and Characterizes Three Loci on Chromosomes 10, 11 and 16

(1) Background: The heritability of breast cancer is partly explained but much of the genetic contribution remains to be identified. Haplotypes are often used as markers of ethnicity as they are preserved through generations. We have previously demonstrated that haplotype analysis, in addition to standard SNP association studies, could give novel and more detailed information on genetic cancer susceptibility. (2) Methods: In order to examine the association of a SNP or a haplotype to breast cancer risk, we performed a genome wide haplotype association study, using sliding window analysis of window sizes 1−25 and 50 SNPs, in 3200 Swedish breast cancer cases and 5021 controls. (3) Results: We identified a novel breast cancer susceptibility locus in 8p21.1 (OR 2.08; p 3.92 × 10−8), confirmed three known loci in 10q26.13, 11q13.3, 16q12.1-2 and further identified novel subloci within these three loci. Altogether 76 risk SNPs, 3302 risk haplotypes of window size 2−25 and 113 risk haplotypes of window size 50 at p < 5 × 10−8 on chromosomes 8, 10, 11 and 16 were identified. In the known loci haplotype analysis reached an OR of 1.48 in overall breast cancer and in familial cases OR 1.68. (4) Conclusions: Analyzing haplotypes, rather than single variants, could detect novel susceptibility loci even in small study populations but the method requires a fairly homogenous study population.

Early detection of pancreatic cancer

Pancreatic ductal adenocarcinoma is most frequently detected at an advanced stage. Such late detection restricts treatment options and contributes to a dismal 5-year survival rate of 3-15%. Pancreatic ductal adenocarcinoma is relatively uncommon and screening of the asymptomatic adult population is not feasible or recommended with current modalities. However, screening of individuals in high-risk groups is recommended. Here, we review groups at high risk for pancreatic ductal adenocarcinoma, including individuals with inherited predisposition and patients with pancreatic cystic lesions. We discuss studies aimed at finding ways of identifying pancreatic ductal adenocarcinoma in high-risk groups, such as among individuals with new-onset diabetes mellitus and people attending primary and secondary care practices with symptoms that suggest this cancer. We review early detection biomarkers, explore the potential of using social media for detection, appraise prediction models developed using electronic health records and research data, and examine the application of artificial intelligence to medical imaging for the purposes of early detection.

Increased risk for uterine cancer among first-degree relatives to Swedish gastric cancer patients

Purpose

In order to further understand genetically predisposing factors of gastric cancer, a retrospective study on 107 patients with gastric cancer was conducted. The family history of cancer cases was registered, in search of associations between gastric cancer and other cancer types.

Materials and methods

Within Stockholm County in Sweden, all patients previously diagnosed with gastric cancer and still alive were invited to participate in the study. Patients were asked to complete a questionnaire about their gastric cancer diagnosis and if any cancers had occurred in their family. A blood sample for DNA extraction was collected. The proportions of different cancer types in the relatives of the patients were compared to the general Swedish population in 1970 and 2010.

Results

Among first- and second-degree relatives to the index patients with gastric cancer, the frequency of uterine cancer as well as gastric cancer was significantly overrepresented compared to the general population in Sweden. The frequency of breast cancer was significantly lower.

Conclusions

There seems to be an increased risk of both gastric cancer and uterine cancer in the families of gastric cancer survivors, indicating a possible hereditary connection between these two cancer types.

Histopathological patterns of primary malignant ovarian neoplasms in different age groups in Almadinah Almunawwarah region, KSA

Objectives

In the literature, the epidemiological pattern of ovarian neoplasms in different age groups in the Almadinah Almunawwarah region in KSA has not been completely elucidated. Moreover, an unusually frequent diagnosis of adult granulosa cell tumour (AGCT) has been observed in patients in Almadinah Almunawwarah, KSA. This study aimed to describe the pattern of ovarian neoplasms in different age groups in the Almadinah Almunawwarah region with particular emphasis on AGCT.

Methods

Histopathological records of all ovarian specimens diagnosed from 2011 January to 2016 December were collected from the Maternity and Children Hospital in Almaadinah Almunawwarah, KSA. Hematoxylin and eosin (HE)-stained microscopic slides of serous and mucinous epithelial borderline neoplasms and of malignant epithelial, sex cord-stromal and germ line neoplasms were identified and examined. The tissue sections from the AGCT were stained immunohistochemically with BRCA-1 antibody.

Results

A total of 301 ovarian specimens were obtained. Of the specimens, 217 (72%) were neoplastic and 84 (28%) were non-neoplastic. In total, 135 (63%) of the neoplastic specimens were benign, 16 (7%) were borderline tumours, and 66 (30%) were malignant tumours. Moreover, 41 (62%) of the malignant tumours were surface epithelial carcinomas, 17 (26%) were sex cord-stromal tumours, and 8 (12%) were germ cell tumours. The incidence of AGCT was unusually high, which accounts for 26% (16/66) of all malignant ovarian neoplasms. Altered BRCA-1 expression was observed in only two specimens.

Conclusion

In this study, malignant ovarian neoplasms accounted for 30% of all neoplastic ovarian specimens, and the incidence of AGCT was remarkable. Such tumours did not show a significantly altered expression of BRCA-1. Further studies must be conducted to explore the underlying molecular causes of this condition.

Alteration of BRCA-1 tumor suppressor gene expression in serous and mucinous ovarian neoplasms in the benign-borderline-malignant pathway

Alteration of expression of the tumor suppressor gene BRCA-1 has been widely studied in breast and ovarian carcinoma. However, pattern of this alteration in the benign-borderline-carcinoma sequence in serous and mucinous ovarian neoplasms have not yet fully described. Tissue sections from 214 formalin-fixed paraffin-embedded ovarian specimens were stained immunohistochemically with BRCA-1 antibody. Specimens were 10 normal ovarian surface epithelium, 10 fallopian tube epithelium, 70 benign adenoma (50 serous and 20 mucinous), 28 borderline (13 serous and 15 mucinous), 78 carcinoma (58 serous and 20 mucinous), and 18 metastatic deposit (13 serous and 5 mucinous). Expression was evaluated into 0, +1, +2, and +3. Score +3 staining similar to normal tissues was considered normal and other scores were considered altered expression. Strong expression was seen in all normal epithelium specimens. Altered expression was seen in 34 serous neoplasms; 17 of 50 (34%) of benign cystadenomas, 6 of 13 (46%) of borderline tumors, 43 of 58 (74%) of primary carcinoma, and in 8 of 13 (62%) of metastatic carcinoma. This alteration was significantly associated with higher histopathologic grade (P = 0.049), presence of necrosis (P = 0.0001), and higher proliferation rate (P = 0.001). In mucinous neoplasms; altered BRCA-1 was detected in 25 specimens; 7 of 20 (41%) of benign cystadenomas, 5 of 15 (33%) of borderline neoplasms, 9 of 20 (45%) of primary carcinoma, and 4 of 5 (80%) of the metastatic deposits. This alteration was not associated with any of the clinicopathologic tumor characteristics. In conclusion, alteration of BRCA-1 expression is more frequent in serous than in mucinous carcinomas and is associated with tumors of higher grades and high proliferation rate.

Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort

Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of our study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers according to current clinical guidelines. The study included 5,122 unselected Swedish breast cancer patients diagnosed from 2001 to 2008. Target sequence enrichment (48.48 Fluidigm Access Arrays) and sequencing were performed (Illumina Hi-Seq 2,500 instrument, v4 chemistry). Differences in patient and tumor characteristics of BRCA1/2 carriers who were already identified as part of clinical BRCA1/2 testing routines and additional BRCA1/2 carriers found by sequencing the entire study population were compared using logistic regression models. Ninety-two of 5,099 patients with valid variant calls were identified as BRCA1/2 carriers by screening all study participants (1.8%). Only 416 study participants (8.2%) were screened as part of clinical practice, but this identified 35 out of 92 carriers (38.0%). Clinically identified carriers were younger, less likely postmenopausal and more likely to be associated with familiar ovarian cancer compared to the additional carriers identified by screening all patients. More BRCA2 (34/42, 81.0%) than BRCA1 carriers (23/50, 46%) were missed by clinical screening. In conclusion, BRCA1/2 mutation prevalence in unselected breast cancer patients was 1.8%. Six in ten BRCA carriers were not detected by selective clinical screening of individuals.

Expression and prognostic significance of Fanconi anemia group D2 protein and breast cancer type 1 susceptibility protein in familial and sporadic breast cancer

Fanconi anemia group D2 protein (FANCD2) and breast cancer type 1 susceptibility protein (BRCA1), within the FA/BRCA pathway, are involved in the regulation of DNA damage repair, which is associated with breast cancer (BC) progression. The present study aimed to investigate BRCA1 and FANCD2 expression in breast cancer, and to highlight the association with patient clinical characteristics and prognoses. The BRCA1 and FANCD2 proteins were detected by immunohistochemistry in 335 tissue samples obtained from patients with BC, including 141 patients with familial BC (FBC), 147 patients with sporadic breast cancer (SBC) and 47 patients with benign breast tumors. Western blotting was used to detect the FANCD2 ubiquitination level in 56 frozen specimens that were randomly selected from the SBC group. Protein expression of BRCA1 in the FBC group was positively associated with tumor size, lymphatic invasion, Tumor-Node-Metastasis (TNM) stage, estrogen receptor (ER) status and FANCD2 expression. Protein expression of FANCD2 in the SBC group was positively associated with tumor size, TNM stage, ER status and Ki-67 index. Survival analyses revealed that BRCA1 expression was associated with the decreased disease-free survival (DFS) rate of patients with FBC (versus no BRCA1 expression) and that FANCD2 was associated with decreased DFS of patients with SBC (versus no FANCD expression). Univariable and multivariable analyses demonstrated that BRCA1 expression may be an independent prognostic factor in the FBC group. In the SBC group, FANCD2 high expression and low ubiquitination levels were considered as independent prognostic factors. In conclusion, the present study suggested that BRCA1 and FANCD2 expression, and FANCD2 ubiquitination levels, may be considered of novel potential prognostic value in patients with BC.

Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer

INTRODUCTION

Heritage is the most important risk factor for breast cancer. About 15-20% of breast cancer is familial, referring to affected women who have one or more first- or second-degree relatives with the disease. The heritable component in these families is substantial, especially in families with aggregation of breast cancer with low age at onset. Identifying breast cancer susceptibility genes: Since the discovery of the highly penetrant autosomal dominant susceptibility genes BRCA1 and BRCA2 in the 1990s, several more breast cancer genes that confer a moderate to high risk of breast cancer have been identified. Furthermore, during the last decade, advances in genomic technologies have led to large scale genotyping in genome-wide association studies that have identified a considerable amount of common low penetrance loci. In total, the high risk genes, BRCA1, BRCA2, TP53, STK11, CD1 and PTEN account for approximately 20% of the familial risk. Moderate risk variants account for up to 5% of the inherited familial risk. The more than 180 identified low-risk loci explain 18% of the familial risk. Altogether more than half of the genetic background in familial breast cancer remains unclear. Other genes and low risk loci that explain a part the remaining fraction will probably be identified. Clinical aspects and future perspectives: Definitive clinical recommendations can be drawn only for carriers of germline variants in a limited number of high and moderate risk genes for which an association with breast cancer has been established. Future progress in evaluating previously identified breast cancer candidate variants and low risk loci as well as exploring new ones can play an important role in improving individual risk prediction in familial breast cancer.

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.