Effects of Neoadjuvant Chemotherapy in Ovarian Cancer Patients With Different Germline BRCA1/2 Mutational Status: A Retrospective Cohort Study

BackgroundWhether neoadjuvant chemotherapy (NAC) followed by interval debulking surgery (IDS) against primary debulking surgery (PDS) has a differential effect on prognosis due to Breast Cancer Susceptibility Genes (BRCA)1/2 mutations has not been confirmed by current studies.MethodsAll patients included in this retrospective study were admitted to Qilu Hospital of Shandong University between January 2009 and June 2020, and germline BRCA1/2 mutation were tested. Patients in stage IIIB, IIIC, and IV, re-staged by International Federation of Gynecology and Obstetrics (FIGO) 2014, were selected for analysis. All patients with NAC received 1-5 cycles of platinum-containing (carboplatin, cisplatin, or nedaplatin) chemotherapy. Patients who received maintenance therapy after chemotherapy were not eligible for this study. All relevant medical records were collected.ResultsA total of 322 patients were enrolled, including 112 patients with BRCA1/2 mutations (BRCAmut), and 210 patients with BRCA1/2 wild-type (BRCAwt). In the two groups, 40 BRCAmut patients (35.7%) and 69 BRCAwt patients (32.9%) received NAC. The progression-free survival (PFS) of BRCAmut patients was significantly reduced after NAC (median: 14.9 vs. 18.5 months; p=0.023); however, there was no difference in overall survival (OS) (median: 75.1 vs. 72.8 months; p=0.798). Whether BRCAwt patients received NAC had no significant effect on PFS (median: 13.5 vs. 16.0 months; p=0.780) or OS (median: 54.0 vs. 56.4 months; p=0.323). Multivariate analyses in BRCAmut patients showed that the predictors of prolonged PFS were PDS (p=0.001), the absence of residual lesions (p=0.012), and FIGO III stage (p=0.020); Besides, PARP inhibitor was the independent predictor for prolonged OS in BRCAmut patients (p=0.000), for BRCAwt patients, the absence of residual lesions (p=0.041) and history of PARP inhibitors (p=0.000) were beneficial factors for OS prolongation.ConclusionsFor ovarian cancer patients with FIGO IIIB, IIIC, and IV, NAC-IDS did not adversely affect survival outcomes due to different BRCA1/2 germline mutational status.

Multilocus Inherited Neoplasia Allele Syndrome (MINAS): an update

Multi-locus Inherited Neoplasia Allele Syndrome (MINAS) refers to individuals with germline pathogenic variants in two or more cancer susceptibility genes(CSGs). With increased use of exome/genome sequencing it would be predicted that detection of MINAS would become more frequent. Here we review recent progress in knowledge of MINAS. A systematic literature search for reports of individuals with germline pathogenic variants in 2 or more of 94 CSGs was performed. In addition, participants with multiple primary tumours who underwent genome sequencing as part of the Rare Disease arm of the UK 100,000 Genomes Project were interrogated to detect additional cases. We identified 385 MINAS cases (211 reported in the last 5 years, 6 from 100,000 genomes participants). Most (287/385) cases contained at least one pathogenic variant in either BRCA1 or BRCA2. 108/385 MINAS cases had multiple primary tumours at presentation and a subset of cases presented unusual multiple tumour phenotypes. We conclude that, as predicted, increasing numbers of individuals with MINAS are being have been reported but, except for individuals with BRCA1/BRCA2 MINAS, individual CSG combinations are generally rare. In many cases it appears that the clinical phenotype is that which would be expected from the effects of the constituent CSG variants acting independently. However, in some instances the presence of unusual tumour phenotypes and/or multiple primary tumours suggests that there may be complex interactions between the relevant MINAS CSGs. Systematic reporting of MINAS cases in a MINAS database (e.g. https://databases.lovd.nl/shared/diseases/04296) will facilitate more accurate prognostic predictions for specific CSG combinations.

BRCA1/BRCA2 mutation spectrum analysis in South Asia: a systematic review

Objective Breast cancer (BC) is the most common form of cancer among Asian females. Mutations in the BRCA1/ BRCA2 genes are often observed in BC cases and largely increase the lifetime risk of having BC. Because of the paucity of high-quality data on the molecular spectrum of BRCA mutations in South Asian populations, we aimed to explore these mutations among South Asian countries. Methods A systematic literature search was performed for the BRCA1 and BRCA2 gene mutation spectrum using electronic databases such as PubMed, EMBASE, and Google Scholar. Twenty studies were selected based on specific inclusion and exclusion criteria. Results The 185delAG (c.68_69del) mutation in exon 2 of BRCA1 was the most common recurrent mutation and founder mutation found. Various intronic variants, variants of unknown significance, large genomic rearrangements, and polymorphisms were also described in some studies. Conclusions The South Asian population has a wide variety of genetic mutations of BRCA1 and BRCA2 that differ according to countries and ethnicities. A stronger knowledge of various population-specific mutations in these cancer susceptibility genes can help provide efficient strategies for genetic testing.

A novel high-throughput assay using mixed genomic DNA for fast screening germline pathogenic variants in breast cancer susceptibility genes

The demand for genetic testing for breast cancer susceptibility genes is increasing for both breast cancer patients and healthy individuals. Here we established a novel high-throughput assay to detect germline pathogenic variants in breast cancer susceptibility genes. In general, up 10 to 50 individual genomic DNA samples were mixed together to create a mixed DNA sample and the mixed DNA sample was subjected to a next-generation multigene panel. Germline pathogenic variants in breast cancer susceptibility genes could be found in the mixed DNA sample; next, site-specific Sanger sequencing was performed to identify individuals who carried he pathogenic variant in the mixed samples. We found that the recall and precision rates were 89.9% and 92.9% when twenty individual genomic samples were mixed. Therefore, our new assay can increase an approximately 20-fold of efficacy to identify the pathogenic variants in breast cancer susceptibility genes in individuals when compared with current assay.

Germline breast cancer susceptibility genes, tumor characteristics, and survival

Background Mutations in certain genes are known to increase breast cancer risk. We study the relevance of rare protein-truncating variants (PTVs) that may result in loss-of-function in breast cancer susceptibility genes on tumor characteristics and survival in 8852 breast cancer patients of Asian descent. Methods Gene panel sequencing was performed for 34 known or suspected breast cancer predisposition genes, of which nine genes (ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, and TP53) were associated with breast cancer risk. Associations between PTV carriership in one or more genes and tumor characteristics were examined using multinomial logistic regression. Ten-year overall survival was estimated using Cox regression models in 6477 breast cancer patients after excluding older patients (≥75years) and stage 0 and IV disease. Results PTV9genes carriership (n = 690) was significantly associated (p < 0.001) with more aggressive tumor characteristics including high grade (poorly vs well-differentiated, odds ratio [95% confidence interval] 3.48 [2.35–5.17], moderately vs well-differentiated 2.33 [1.56–3.49]), as well as luminal B [HER−] and triple-negative subtypes (vs luminal A 2.15 [1.58–2.92] and 2.85 [2.17–3.73], respectively), adjusted for age at diagnosis, study, and ethnicity. Associations with grade and luminal B [HER2−] subtype remained significant after excluding BRCA1/2 carriers. PTV25genes carriership (n = 289, excluding carriers of the nine genes associated with breast cancer) was not associated with tumor characteristics. However, PTV25genes carriership, but not PTV9genes carriership, was suggested to be associated with worse 10-year overall survival (hazard ratio [CI] 1.63 [1.16–2.28]). Conclusions PTV9genes carriership is associated with more aggressive tumors. Variants in other genes might be associated with the survival of breast cancer patients. The finding that PTV carriership is not just associated with higher breast cancer risk, but also more severe and fatal forms of the disease, suggests that genetic testing has the potential to provide additional health information and help healthy individuals make screening decisions.

Mutational Spectrum of Breast Cancer Susceptibility Genes among Women in Northeast Brazil

Purpose: There is a paucity of data on the spectrum and prevalence of pathogenic variants among women of African ancestry in the Northeast region of Brazil. Methods: We performed BROCA panel sequencing to identify inherited loss-of-function variants in breast cancer susceptibility genes among 292 Brazilian women referred to a single institution cancer risk assessment program. Results: The study included a convenient cohort of 173 women with invasive breast cancer and 119 women who were cancer-free at the time of ascertainment. The majority of the women self-reported as African-descended (67% for cases and 90.8% for controls). Thirty-seven pathogenic variants were found in 36 (20.8%) patients. While the spectrum of pathogenic variants was heterogeneous, the majority (70.3%) of the pathogenic variants were detected in high-risk genes BRCA1 , BRCA2 , PALB2 , and TP53 . Pathogenic variants were also found in the ATM , BARD1 , BRIP1 , FAM175A , FANCM , NBN , and SLX4 genes in 6.4% of the affected women. Four recurrent pathogenic variants were detected in 11 patients of African ancestry. Only one unaffected woman had a pathogenic variant in the RAD51C gene. Conclusion: The high prevalence and heterogenous spectrum of pathogenic variants identified among self-reported African descendants in Northeast Brazil is consistent with studies in other African populations with a high burden of aggressive young onset breast cancer. It underscores the need to integrate comprehensive cancer risk assessment and genomic testing in the management of newly diagnosed Black women with breast cancer across the African Diaspora, enabling improved cancer control in admixed underserved and understudied populations.

Exonic sequencing and MLH3 gene expression analysis of breast cancer patients

Breast cancer is the most common cancer in women worldwide. Detection of breast cancer susceptibility genes is an important issue. Also, MLH3 is a DNA mismatch repair gene and mutation in this gene is harmful in different cancers. This study aimed to use exome sequencing to uncover previously undetected breast cancer-predisposing variants. Also, we investigated the MLH3 gene expression of breast cancer patients which can be a breast cancer susceptibility gene. A total of 80 samples including 40 paired normal and cancer tissue samples were collected at Zheen International Hospital, Erbil, Iraq. Exome sequencing was used to identify mutations. Different in silico tools were used to predict the effect of mutation on the structural features or protein function. Real-time PCR was used for assessing the expression of MLH3 in breast cancer patients. We identified 26 variants in breast cancer patients, 22 inherited variants were found in MLH3, CHECK2, BRCA1, BRCA2, BLM, TP53, MSH6, NBN and PTEN genes and 4 somatic variants were found in PALB2, RAD50 and RBM10 genes. It was found that the expression of the MLH3 gene in tumor samples was significantly down-regulated compared with normal tissues. Statistically, high significance was found. The decreased expression of MLH3 was significant in all ranges of ages and all breast cancer types. Also, the expression of MLH3 decreased significantly in patients with breast cancer grades of II and III. In conclusion, MLH3 can be used as a susceptibility gene especially in grades II and III of breast cancer.

Germline Testing Data Validate Inferences of Mutational Status for Variants Detected From Tumor-Only Sequencing

PURPOSE Pathogenic germline variants (PGVs) in cancer susceptibility genes are usually identified through germline testing of DNA from blood or saliva: their detection can affect treatment options and potential risk-reduction strategies for patient relatives. PGV can also be identified in tumor sequencing assays, which, when performed without patient-matched normal specimens, render determination of variants' germline or somatic origin critical. METHODS Tumor-only sequencing data from 1,608 patients were retrospectively analyzed to infer germline versus somatic status of variants using an information-theoretic, gene-independent approach. Loss of heterozygosity was also determined. Predicted mutational models were compared with clinical germline testing results. Statistical measures were computed to evaluate performance. RESULTS Tumor-only sequencing detected 3,988 variants across 70 cancer susceptibility genes for which germline testing data were available. We imputed germline versus somatic status for > 75% of all detected variants, with a sensitivity of 65%, specificity of 88%, and overall accuracy of 86% for pathogenic variants. False omission rate was 3%, signifying minimal error in misclassifying true PGV. A higher portion of PGV in known hereditary tumor suppressors were found to be retained with loss of heterozygosity in the tumor specimens (72%) compared with variants of uncertain significance (58%). CONCLUSION Analyzing tumor-only data in the context of specimens' tumor cell content allows precise, systematic exclusion of somatic variants and suggests a balance between type 1 and 2 errors for identification of patients with candidate PGV for standard germline testing. Although technical or systematic errors in measuring variant allele frequency could result in incorrect inference, misestimation of specimen purity could result in inferring somatic variants as germline in somatically mutated tumor suppressor genes. A user-friendly bioinformatics application facilitates objective analysis of tumor-only data in clinical settings.

Association of Family Cancer History With Pathogenic Variants in Specific Breast Cancer Susceptibility Genes

PURPOSE Family cancer history is an important component of genetic testing guidelines that estimate which patients with breast cancer are most likely to carry a germline pathogenic variant (PV). However, we do not know whether more extensive family history is differentially associated with PVs in specific genes. METHODS All women diagnosed with breast cancer in 2013-2017 and reported to statewide SEER registries of Georgia and California were linked to clinical genetic testing results and family history from two laboratories. Family history was defined as strong (suggestive of PVs in high-penetrance genes such as BRCA1/2 or TP53, including male breast, ovarian, pancreatic, sarcoma, or multiple female breast cancers), moderate (any other cancer history), or none. Among established breast cancer susceptibility genes ( ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, NF1, PALB2, PTEN, RAD51C, RAD51D, and TP53), we evaluated PV prevalence according to family history extent and breast cancer subtype. We used a multivariable model to test for interaction between affected gene and family history extent for ATM, BRCA1/2, CHEK2, and PALB2. RESULTS A total of 34,865 women linked to genetic results. Higher PV prevalence with increasing family history extent ( P < .001) was observed only with BRCA1 (3.04% with none, 3.22% with moderate, and 4.06% with strong history) and in triple-negative breast cancer with PALB2 (0.75% with none, 2.23% with moderate, and 2.63% with strong history). In a multivariable model adjusted for age and subtype, there was no interaction between family history extent and PV prevalence for any gene except PALB2 ( P = .037). CONCLUSION Extent of family cancer history is not differentially associated with PVs across established breast cancer susceptibility genes and cannot be used to personalize genes selected for testing.

Heterozygous Pathogenic Nonsense ATM Variant Resulting in Unusually High Gastric Cancer Susceptibility

We describe the unusual presentation of familial early-onset gastric cancer due to a heterozygous pathogenic variant in the ATM gene. The proband had gastric cancer (age 45), and reported a sister deceased for diffuse gastric cancer (age 30) and another sister who developed diffuse gastric cancer (age 52) and ovarian serous cancer. Next Generation Sequencing for cancer susceptibility genes (APC, ATM, BRD1, BRIP1, CDH1, CDK4, CDKN2A, CHEK2, EPCAM, MLH1, MRE11, MSH2, MSH6, MUTYH, NBN, PALB2, PMS2, PTEN, RAD50, RAD51C, RAD51D, RECQL1, SMAD4, STK11, TP53) identified the truncating c.5944C>T, p.(Gln1982*) variant in ATM (NM_000051.3; NP_000042.3) in the proband. The variant segregated in the living affected sister and in the unaffected daughter of the deceased sister. Heterozygous ATM variants appear to significantly increase the risk for pancreatic, breast, gastric and prostatic cancer and, to a reduced extent, ovarian and colon cancer and melanoma, with moderate penetrance and variable expressivity. Familial gastric cancer is an unusual presentation for ATM. The occurrence of gastric cancer in this family suggests that individual variants may result in different, specific risks. Genotype-phenotype correlations are challenging, given the low penetrance and variable expressivity for ATM variants. Careful family history assessment is pivotal for prevention planning, strengthened by the availability of molecular diagnoses.