Germline Mutation Carriers Research Articles

BRCA2 and Other DDR Genes in Prostate Cancer.

Germline and somatic aberrations in DNA damage repair (DDR) genes are more prevalent in prostate cancer than previously recognized, with BRCA2 as the most commonly altered gene. Germline mutations in BRCA2 have been linked to poor prognosis when patients are managed under the protocols currently approved for prostate cancer. The impact of germline mutations in other DDR genes beyond BRCA2 remain unclear. Importantly, a quarter of prostate cancer patients identified as germline mutation carriers lack a family history of cancer. The clinical implications of somatic DDR defects are yet to be elucidated. Poly ADP-ribose polymerase (PARP) inhibitors and platinum-based chemotherapy have proven to be effective in the treatment of other tumor types linked to BRCA1 and BRCA2 alterations and several trials are currently evaluating their efficacy in prostate cancer. Here, we summarize the available evidence regarding the prevalence of somatic and germline DDR defects in prostate cancer; their association with clinical outcomes; the trials assessing the efficacy of new therapies that exploit DDR defects in prostate cancer and briefly discuss some uncertainties about the most appropriate management for these patients.

Prophylactic irradiation to the contralateral breast for BRCA mutation carriers with early-stage breast cancer

Women who carry germ-line mutations in BRCA1/2 are at very high risk of developing breast and ovarian cancer. Breast conserving therapy is associated with a similar risk of ipsilateral cancer recurrence in BRCA carriers compared with non-carriers. However, the risk of subsequent contralateral breast cancer in carriers is markedly increased. Therefore, mastectomy of the diseased breast along with risk reducing mastectomy of the contralateral breast is often advocated for BRCA carriers who are treated for early breast cancer. Yet, many BRCA carriers forgo this option for fear of harmful effects and choose breast conserving treatment and observation instead. In Israel, BRCA-associated breast cancer is relatively common. Accordingly, a national protocol was devised for this enriched population. In this Institutional Review Board-approved phase II trial, the option of prophylactic irradiation to the contralateral breast, in addition to standard loco-regional treatment, was offered to BRCA carrier patients treated for early breast cancer who declined contralateral mastectomy. The primary end point was contralateral breast cancer. Between May 2007 and October 2017, 162 patients were enrolled. Eighty-one patients opted for standard loco-regional treatment including surgery and radiation to the involved side (control arm) and 81 patients chose additional contralateral breast irradiation (intervention arm). At a median follow-up of 58 months, 10 patients developed contralateral breast cancer in the control arm at a median of 32 months, as compared with 2 patients in the intervention arm who developed contralateral breast cancer 80 and 105 months after bilateral breast irradiation (log-rank P = 0.011). Among BRCA carrier patients treated for early breast cancer, the addition of contralateral breast irradiation was associated with a significant reduction of subsequent contralateral breast cancers and a delay in their onset. Phase II, comparative two-arm trial (NCT00496288).

Abstract P4-04-01: The landscape of somatic genetic alterations in breast cancers from CHEK2 germline mutation carriers

Abstract Introduction: Checkpoint kinase 2 (CHEK2) is a tumor suppressor gene, which regulates cell cycle in response to DNA damage response. Selected CHEK2 germline mutations have been shown to confer an increased risk of breast cancer development. Multiple founder mutations in CHEK2 have been identified, and meta analyses have shown that CHEK2 truncating variants confer a higher breast cancer risk than missense variants. Here, we assessed the phenotype and repertoire of genetic alterations of breast cancers from 33 patients with CHEK2 pathogenic germline variants. Materials and methods: We performed targeted capture massively parallel sequencing (≥410 genes) of tumor and normal samples from 13 patients with CHEK2 pathogenic germline variants, and retrieved whole exome sequencing (WES) data (BAM files) of tumor and normal samples from 20 patients with CHEK2 germline pathogenic variants included in the TCGA breast cancer study. In addition, we retrieved WES data of BRCA1, BRCA2 and ATM associated breast cancers from TCGA and Weigelt et al. (JNCI 2018). Somatic mutations, copy number alterations, mutational signatures and large-scale transitions (LSTs) were defined using state-of-the-art bioinformatics algorithms. Results: Of the 33 CHEK2-associated breast cancers included in this study, 21 had missense and 12 had loss-of-function (LoF) germline mutations, and 81% were ER-positive and 12% HER2-positive. CHEK2-associated breast cancers statistically significantly less frequently displayed an ER-negative/HER2-negative phenotype (0%) than BRCA1- (80%) or BRCA2-associated (33%) breast cancers (BRCA1, p<0.0001 for both comparisons), but were similar to ATM-associated breast cancers. Biallelic inactivation of CHEK2 through loss of heterozygosity (LOH) of the wild-type allele was present in 17 of 33 samples (52%). LOH of the CHEK2 wild-type allele was significantly more frequent in tumors with LOF mutations than in those with missense mutations (78% vs 36%, respectively; p=0.0394). PIK3CA (36%) and GATA3 (33%) were the two most recurrently mutated genes in these samples. TP53 somatic mutations were detected in five cases, four of which harbored missense CHEK2 germline mutations. Unlike BRCA1- and BRCA2-associated breast cancers, but akin to ATM-associated breast cancers, CHEK2-associated breast cancers lacked the mutational signature associated with homologous recombination (HR) DNA repair defects (i.e. signature 3) and only five cases displayed high LST scores. Conclusion:CHEK2-associated breast cancers are phenotypically and genetically distinct from BRCA1- and BRCA2-associated breast cancers, but similar to ATM-associated breast cancers. Akin to ATM-associated breast cancers, CHEK2-associated breast cancers are preferentially ER-positive, lack genomics features consistent with defective HR, and have a repertoire of somatic genetic alterations similar to those of non-BRCA1/2 ER-positive breast cancers. Our results suggest that either CHEK2 germline mutations contribute to an increased risk of breast cancer independently of the HR DNA repair defects or that the mutational signatures caused by CHEK2 pathogenic germline mutations differ from those caused by pathogenic germline mutations affecting bona fide HR-related genes (e.g. BRCA1, BRCA2 and PALB2). Citation Format: Kumar R, Pei X, Selenica P, Wen HY, Powell S, Robson M, Riaz N, Reis-Filho JS, Weigelt B, Mandelker D. The landscape of somatic genetic alterations in breast cancers from CHEK2 germline mutation carriers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-01.

Abstract ES12-2: Link between BRCA1 and Pol II pausing in mammary gland development and tumorigenesis

Abstract Breast cancer risk is significantly elevated for women who carry germ-line mutations in the tumor suppressor gene BRCA1. BRCA1-asociated breast tumors are basal-like, yet they originate from luminal progenitor cells. These precancerous cells of origin are defective in luminal differentiation in BRCA1 mutation carriers before any clinical evidence of cancer. While BRCA1 is best known for its functions in double strand break DNA repair and response to DNA replication stress, it is unclear whether loss of these ubiquitously important functions of BRCA1 is sufficient to account for lineage-specific breast tumor development in BRCA1 mutation-carrying women. Filling this longstanding intellectual disconnect could inform more effective risk assessment and disease prevention. Recent discoveries from others and us challenge the prevailing DNA repair/replication-centric paradigm. First, in vitro studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcription and genetic instability. Using breast tissue of cancer-free BRCA1 mutation-carrying women, we show that R-loops accumulate preferentially in breast luminal epithelial cells, not in basal epithelial or stromal cells, of BRCA1 mutation carriers. Furthermore, R-loops are enriched at the 5' end of those genes with promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of Cobra1, which encodes a Pol II-pausing and BRCA1-binding protein, ameliorates R-loop accumulation and reduces tumorigenesis in Brca1 knockout mouse mammary epithelium. Of note, this BRCA1/COBRA1 interaction occurs in a DSB repair-independent manner. Based on these findings, we suggest that as part of its tumor suppressor activity, BRCA1 promotes luminal epithelial differentiation by mitigating Pol II pausing-dependent transcriptional stress at luminal fate genes. We further propose that accumulation of transcriptional stress in BRCA1-deficient luminal cells redirects luminal transcription and alters luminal homeostasis, which ultimately contributes to lineage-specific BRCA1-associated tumorigenesis. Citation Format: Li R. Link between BRCA1 and Pol II pausing in mammary gland development and tumorigenesis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr ES12-2.

Abstract P1-09-07: Breast cancer characteristics and outcomes in patients with TP53 germline mutation

Abstract Introduction Li-Fraumeni syndrome (LFS) resulting from monoallelic germline TP53 gene mutation is a rare hereditary cancer predisposition. Breast cancer (BC) is the most common cancer among women with TP53 germline mutation with a risk ranging from 49% to 85% by the age of 60 years old. Most of these cancers are early onset. Few patients' cases have been reported so far in the literature. Our aim was to describe the medical history of a cohort of LFS women diagnosed with BC recruited from a single institution. The characteristics combined were genetic alteration diagnosis, tumor characteristics, treatment, outcome, and LFS associated cancers. Methods We retrospectively identified breast cancer patients with TP53 germline mutation from the Institut Curie (Paris, France) database and described their cancer characteristics and medical history. Results From 1989 to 2015, 25 patients affected with BC (31 tumors) and TP53 germline mutation carrier were identified, with a median follow up of 6.5 years. Median age at BC diagnosis was 30.5 years. All patients were women. 33% had a previously identified TP53 mutation in their family. 70% of them had BC as their first cancer event. 60% of the patients presented with another LFS associated cancer or non-related cancers: osteosarcoma (22%), glioblastoma (18%), pulmonary carcinoma (13%), gastric linitis plastica (9%), malignant hemopathy (9%), soft tissue sarcoma (9%), adrenocortical carcinoma (4%), ovarian cystadenocarcinoma (4%), renal tumor (4%), choroid plexus carcinoma (4%). 92% of the breast tumors were ductal carcinoma (28% DCIS and 64% IDC), 7% were sarcoma (1 phyllodesarcoma, 1 pleiomorphic liposarcoma); there were no lobular carcinoma. Among the IDC, 50% were HER2 positive, 72% were hormone-receptor positive. Most patients had a mastectomy (64%), and most of them received radiation (55%). However, when TP53 mutation had been identified prior to the treatment, none of the patients received radiotherapy (5 patients). Most patients received chemotherapy (70%) (37% in neoadjuvant setting, 33% in adjuvant setting, 25% for metastatic setting). 40% of the patients received hormone therapy (37% as adjuvant treatment, 7% for metastatic disease) Most of the patients did not relapse from BC (75%). Overall, only 17% of the patients had metastatic BC. To date, 12 patients of our series have died (48%), 6 patients (24%) from other LFS-associated cancers and 4 patients from BC (16%). Conclusion To the best of our knowledge, this descriptive series is the largest study of tumor characteristics and medical history of LFS-women with BC, the most frequent cancer among women with TP53 germline mutation. It confirms the higher HER2 overexpression rate observed in LFS-patients BC, as suggested in the literature and showed a high rate of DCIS at initial presentation. Most of the patients developed other LFS-associated cancers. In depth molecular analysis of these BC will be performed in order to gain insight into their biological specificities and to adapt the therapeutic management of this poor prognosis syndrome. Citation Format: Tran M, Loirat D, Colas C, Bozec L, Laurence V, Lerebours F, Cabel L, Bidard F-C, Stoppa-Lyonnet D, Vincent-Salomon A, Gauthier-Villars M, Lavigne M, De Pauw A. Breast cancer characteristics and outcomes in patients with TP53 germline mutation [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-09-07.

Abstract P5-10-01: Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology

Abstract Approximately 10-15% of breast cancers are associated with a strong family history of disease. Pathogenic variants in BRCA1, BRCA2 or other moderate to highly penetrant susceptibility genes (e.g. TP53, ATM, CHEK2, PALB2 and PTEN) account for a number of breast cancer families. However, for over 50% of families the underlying genetic contribution to their risk remains unknown (termed here as non-BRCA1/2). This has a profound impact for how individuals and their families are managed in the clinic. We applied whole genome sequencing (WGS) to determine whether somatic mutation analysis can reveal insight into the aetiology of familial breast cancer. The full repertoire of somatic mutations was evaluated in 26 BRCA1, 22 BRCA2 and 32 non-BRCA1/2 tumours; including SNPs, indels, copy number changes and structural rearrangements, and mutational signatures. Genomes were also analysed using the HRD Index and HRDetect, as predictors of homologous recombination deficiency. BRCA1, BRCA2 and non-BRCA1/2 tumours exhibited a different burden of mutations, a different spectrum of mutational signatures and different telomere length. Based on collective patterns of mutation signatures, tumours were classified as 'BRCA1-like', 'BRCA2-like' or 'non-BRCA1/2-like' with a 15% rate of tumour re-classification from their original clinical BRCA status. The results demonstrate the power of WGS to differentiate between BRCA1 and BRCA2 driven tumours; in the identification of double-pathogenic germline mutation carriers based on the resulting somatic mutation signature; and in the interpretation of BRCA unclassified variants. WGS of tumour genomes reveals fascinating insights into tumour aetiology and could compliment current genetic testing of breast cancer families. Citation Format: Simpson P, Nones K, Johnson J, Newell F, Patch A-M, Thorne H, Kazakoff S, De Luca X, Parsons M, Ferguson K, Reid L, McCart Reed A, Srihari S, Lakis V, Davidson A, Mukhopadhyay P, Holmes O, Xu Q, Wood S, Leonard C, Beasley J, Degasperi A, Nik-Zainal S, Ragan M, Spurdle A, Khanna KK, Lakhani S, Pearson J, Chenevix-Trench G, Waddell N. Using whole genome sequencing and somatic mutation signatures to unravel insight into familial breast cancer aetiology [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-10-01.

Prevalence of Germline Mutations Associated With Cancer Risk in Patients With Intraductal Papillary Mucinous Neoplasms

Many patients with pancreatic adenocarcinoma carry germline mutations associated with increased risk of cancer. It is not clear whether patients with intraductal papillary mucinous neoplasms (IPMNs), which are precursors to some pancreatic cancers, also carry these mutations. We assessed the prevalence of germline mutations associated with cancer risk in patients with histologically confirmed IPMN. We obtained nontumor tissue samples from 315 patients with surgically resected IPMNs from 1997 through 2017, and we sequenced 94 genes with variants associated with cancer risk. Mutations associated with increased risk of cancer were identified and compared with individuals from the Exome Aggregation Consortium. We identified 23 patients with a germline mutation associated with cancer risk (7.3%; 95% confidence interval, 4.9-10.8). Nine patients had a germline mutation associated with pancreatic cancer susceptibility (2.9%; 95% confidence interval, 1.4-5.4). More patients with IPMNs carried germline mutations in ATM (P < .0001), PTCH1 (P < .0001), and SUFU (P < .0001) compared with controls. Patients with IPMNs and germline mutations associated with pancreatic cancer were more like to have concurrent invasive pancreatic carcinoma compared with patients with IPMNs without these mutations (P < .0320). In sequence analyses of 315 patients with surgically resected IPMNs, we found that almost 3% to carry mutations associated with pancreatic cancer risk. More patients with IPMNs and germline mutations associated with pancreatic cancer had concurrent invasive pancreatic carcinoma compared with patients with IPMNs without these mutations. Genetic analysis of patients with IPMNs might identify those at greatest risk for cancer.

Leptomeningeal carcinomatosis in BRCA-mutated pancreatic cancer.

239 Background: Pancreatic adenocarcinoma is a rapidly fatal cancer with 5-year overall survival &lt;5%. 5-10% of pancreatic cancers occur in patients with family history of disease, and 5-27% of these familial cancers are BRCA associated, with defects in Homologous Recombination Repair (HRR). In breast and ovarian cancer, BRCA mutations may be associated with increased risk for brain metastasis (BM). BM is rare in pancreatic cancer, but it is suggested HRR deficient pancreatic cancer patients may have an increased risk for BM/LC. Methods: We analyzed 3030 prospectively identified patients with pancreatic cancer and HHR mutation germline sequencing data (BRCA1/2, ATM, PALB2) from the Mayo Clinic Pancreatic Cancer SPORE Registry. We used clinical databases (2000-2018) to assess the presence of BM or leptomeningeal carcinomatosis (LC). Unconditional logistic regression analysis, with Odds Ratio (OR) and 95% Confidence Interval (CI), assessed the association between HRR gene germline mutation carrier status and any BM. Results: Of 3030 total pancreatic cancer patients, 8 were diagnosed with clinically evident BM/LC (0.26%), confirming the very low incidence of this metastasis site (Table). Of these, all had BM, and 4 also had LC present. No patients had LC diagnosed without BM present. 175/3030 (5.8%) patients had a germline HHR gene mutation. Of these, 1 patient was a BRCA2 carrier (0.57% of HRR deficient patients). 7 /2763 (0.25%) patients without germline HRR mutations had BM or LC (p = 0.44, OR 2.26; 95% CI: 0.27, 18.49). Conclusions: To our knowledge, this is the largest review of BRCA-associated pancreatic cancer patients with BM or LC. The incidence of BM is rare at 0.27%, with LC at 0.14%. Limitations include likely underdiagnosis given short clinical course and lack of availability of somatic HRR gene status. Our study suggests HRR germline carrier patients may have an increased risk of BM/LC development compared to non-carriers. Given rarity, larger studies should be explored. [Table: see text]

Analysis of Prophylactic Salpingo-oophorectomy at the Time of Hysterectomy for Benign Lesions.

Background:Prophylactic salpingo-oophorectomy refers to the removal of clinically normal ovaries at the time of hysterectomy for benign lesions, to reduce the risk of ovarian and breast cancer in future. This risk reduction holds true for high-risk women, i.e., those with strong family history of breast or/and ovarian cancer and those who carry germline mutations (BRCA-1 and BRCA-2). However, it is still one of the commonly performed surgeries in low-risk women and has fallen into controversy. It is said that the number needed to treat is 300.Aims and Objectives:The aim of the study was to analyze and understand the reasons behind women opting for prophylactic oophorectomy in spite of the available evidence. We also aimed to study the histopathology reports of the ovaries and tubes removed prophylactically.Material and Methods:This was a prospective study carried out at a tertiary care center which serves both rural and urban population. Of the 252 patients counseled, 86 patients who opted for prophylactic salpingo-oophorectomy were included in the study. A detailed history, clinical examination, relevant investigations (ultrasonography and CA 125 levels), indications for hysterectomy, reasons for prophylactic oophorectomy, intraoperative findings, and the histopathology findings were noted.Results:Main reasons for opting for prophylactic oophorectomy were lack of understanding and thus dependent on their treating doctor for the decision-making, fear of ovarian malignancy in future, inability to follow-up, and previous one or more abdominal surgeries.Conclusion:We as gynecologists need to reconsider the age at which we recommend prophylactic oophorectomy. Too much negative counseling should be deferred.

Generation of induced pluripotent stem cell lines from two Neuroblastoma patients carrying a germline ALK R1275Q mutation

Neuroblastoma (NB) is an embryonic tumor of the peripheral nervous system and one of the most common solid cancers in infants. Mutations in the Anaplastic lymphoma tyrosine kinase (ALK) gene are common in NB. To study the contribution of ALK mutations in NB initiation and progression, we reprogrammed fibroblasts from two related NB patients carrying germline mutations in ALK (R1275Q) using non-integrating Sendai virus. The iPS cells are grown in a feeder- and xeno-free conditions, have normal karyotype, retain the ALK R1275Q mutation, have been characterized by expression of pluripotency markers and differentiation to all three germ layers.

Early Hereditary Diffuse Gastric Cancer (eHDGC) is Characterized by Subtle Genomic Instability and Active DNA Damage Response.

Diffuse gastric cancer (DGC) is one of the two primary types of stomach cancer. Carriers of germline mutations in the gene encoding E-cadherin are predisposed to DGC. The primary aim of the present study was to determine if genomic instability is an early event in DGC and how it may lead to disease progression. Chromosomal aberrations in early intramucosal hereditary diffuse gastric cancer (eHDGC) were assessed using array comparative genomic hybridization (array CGH). Notably, no aneuploidy or other large-scale chromosomal rearrangements were detected. Instead, all aberrations affected small regions (< 4.8Mb) and were predominantly deletions. Analysis of DNA sequence patterns revealed that essentially all aberrations possessed the characteristics of common fragile sites. These results and the results of subsequent immunohistochemical examinations demonstrated that unlike advanced DGC, eHDGCs is characterized by low levels of genomic instability at fragile sites. Furthermore, they express an active DNA damage response, providing a molecular basis for the observed indolence of eHDGC. This finding is an important step to understanding the pathology underlying natural history of DGC and supports a revision of the current definition of eHDGC as a malignant disease.

A Recurrent BRCA2 Mutation Explains the Majority of Hereditary Breast and Ovarian Cancer Syndrome Cases in Puerto Rico.

Breast cancer is the most common cause of cancer diagnosis in women and is responsible for considerable mortality among the women of Puerto Rico. However, there are few studies in Puerto Rico on the genetic factors influencing risk. To determine the contribution of pathogenic mutations in BRCA1 and BRCA2, we sequenced these genes in 302 cases from two separate medical centers, who were not selected for age of onset or family history. We identified nine cases that are carriers of pathogenic germline mutation. This represents 2.9% of unselected cases and 5.6% of women meeting National Comprehensive Cancer Network (NCCN) criteria for BRCA testing. All of the identified pathogenic mutations were in the BRCA2 gene and the most common mutation is the p.Glu1308Ter (E1308X) mutation in BRCA2 found in eight out of nine cases, representing 89% of the pathogenic carriers. The E1308X mutation has been identified in breast and ovarian cancer families in Spain, and analysis of flanking DNA polymorphisms shows that all E1308X carriers occur on the same haplotype. This is consistent with BRCA2 E1308X being a founder mutation for the Puerto Rican population. These results will contribute to better inform genetic screening and counseling of breast and ovarian cancer cases in Puerto Rico and Puerto Rican populations in mainland United States.

Subtypes in BRCA-mutated breast cancer

Approximately 3% to 5% of breast cancer patients are BRCA1 or BRCA2 germline mutation carriers. In this study, we correlated the distribution of intrinsic molecular subtypes according to failure pattern in a Danish cohort of BRCA germline–mutated breast cancer patients. Tumor tissues from 425 BRCA germline–mutated breast cancer patients were analyzed by immunohistochemistry for hormone receptor status, proliferation index (Ki-67), and HER2. Surrogate intrinsic molecular subtypes were assigned according to approximated St Gallen criteria. Annual hazard rates (AHR) were calculated for death and local or distant relapse, contralateral breast cancer, new primary cancer other than breast cancer, or death as first event (disease-free event). Luminal A–like subtype was observed with a frequency of 9% and 35% for BRCA1 and BRCA2, respectively, and for both BRCA1 and BRCA2 patients, the luminal B–like subtype was more frequent than the luminal A–like subtype (BRCA1 21% and BRCA2 40% luminal B–like). No events or deaths were observed for luminal A–like subtype during the first 2.5 and 0 to 5 years, respectively. AHRs for luminal B–like tumors were 5.34% (95% confidence interval [CI], 1.49-1.19) and 1.76% (95% CI, 0.36-3.16) for disease-free event and death, respectively, and those for basal-like were 6.58% (95% CI, 2.98-10.18) and 4.54% (95% CI, 2.69-6.40). A substantial proportion of BRCA carriers had luminal A–like subtype, and these were mainly BRCA2 carriers. Luminal A–like subtype was significantly associated with low AHR the first 5 years after surgery. This study warrants further exploration of the impact of the molecular intrinsic subtypes on survival in BRCA-mutated breast cancer patients.

991P - Clinical characteristics of ovarian cancer relapse in BRCA1/2 germ-line mutation carriers and non-carriers

991P - Clinical characteristics of ovarian cancer relapse in BRCA1/2 germ-line mutation carriers and non-carriers

Synonymous mutation adenomatous polyposis coliΔ486s affects exon splicing and may predispose patients to adenomatous polyposis coli/mutY DNA glycosylase mutation‑negative familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominant-inherited colorectal cancer. Recent advances in genetics have indicated that the majority of patients with FAP carry germline mutations of the adenomatous polyposis coli (APC) and mutY DNA glycosylase (MUTYH) genes. However, a large subset of families with a history of FAP have undetectable pathogenic alterations, termed APC/MUTYH mutation-negative FAP. To investigate the germline mutations in the APC and MUTYH genes in Chinese patients with FAP, 13 unrelated patients were enrolled. Through genetic sequencing, four known pathogenic alterations (Lys1061LysfsTer2, Glu1309AspfsTer4, Arg283Ter and Ser1196Ter) of APC and two novel disease-associated pathogenic mutations (Tyr152Ter and Ter522Gly) in MUTYH were identified in six individuals. For samples that did not present with pathogenic alterations, the functional effects of missense, synonymous and intronic mutations were analyzed using bioinformatics tools and databases. Bioinformatics prediction suggested that the synonymous mutation Tyr486Tyr in APC (APC∆486s) was likely a disease-causing polymorphism and may have induced the exon skipping of APC. A hybrid mini-gene assay was performed, which confirmed that the synonymous single nucleotide polymorphism APC∆486s induced major splicing defects with skipping of exon 12 in APC. The data of the present study suggested that the synonymous polymorphism APC∆486s was a potential pathogenic alteration that predisposed APC/MUTYH mutation-negative patients to FAP.

DICER1 mutations are frequent in adolescent-onset papillary thyroid carcinoma

Thyroid cancer in children and adolescents has a higher rate of regional and distant metastases, and recurrence rate than in adults. However, little is known about the molecular origin of thyroid carcinoma in children. DICER1 encodes for an endoribonuclease responsible for processing RNA into small interfering RNA vand miRNA. DICER1 syndrome (OMIM #601200) has been recently described resulting from truncating mutations in the DICER1 gene causing a wide spectrum of benign and malignant tumors in children, such as pleuropulmonary blastoma, cystic nephroma, and pituitary blastoma. The risk for multinodular goiter and thyroid cancer in DICER1 germline mutation carriers has recently been shown to be highly increased1.

9O - Novel mechanism of platinum resistance: Rapid selection of pre-existing BRCA1-proficient tumor cells during neoadjuvant chemotherapy (NACT) for ovarian cancer (OC) in BRCA1 germ-line mutation carriers

9O - Novel mechanism of platinum resistance: Rapid selection of pre-existing BRCA1-proficient tumor cells during neoadjuvant chemotherapy (NACT) for ovarian cancer (OC) in BRCA1 germ-line mutation carriers

Comprehensive Proteomic Profiling–derived Immunohistochemistry-based Prediction Models for BRCA1 and BRCA2 Germline Mutation-related Breast Carcinomas

Heredity, mostly due to BRCA germline mutations, is involved in 5% to 10% of all breast cancer cases. Potential BRCA germline mutation carriers may be missed following the current eligibility criteria for BRCA genetic testing. The purpose of this study was to, therefore, develop an immunohistochemistry-based model to predict likelihood of underlying BRCA1 and BRCA2 germline mutations in unselected female breast cancer patients. The study group consisted of 100 BRCA1-related, 46 BRCA2-related, and 94 sporadic breast carcinomas. Tumor expression of 44 proteins involved in (BRCA-related) breast carcinogenesis was assessed by immunohistochemistry. A prediction model for BRCA-related versus non-BRCA-related breast cancer was developed using Lasso logistic regression analysis with cross-validation. The model was assessed for its discriminative value and clinical usefulness. The optimal prediction model included 14 predictors (age, cyclinD1, ERα, ERβ, FGFR2, FGFR3, FGFR4, GLUT1, IGFR, Ki67, mitotic activity index, MLH1, p120, and TOP2A), showed excellent discriminative performance (area under the receiving operating characteristic curve=0.943; 95% confidence interval=0.909-0.978), and reasonable calibration. To enhance possible implementation, we developed an alternative model only considering more widely available immunostains. This model included 15 predictors (age, BCL2, CK5/6, CK8/18, cyclinD1, E-cadherin, ERα, HER2, Ki67, mitotic activity index , MLH1, p16, PMS2, PR, and vimentin), and still showed very good discriminative performance (area under the receiving operating characteristic curve=0.853; 95% confidence interval=0.795-0.911). We present a well-applicable and accurate tool to predict which breast cancer patients may have an underlying BRCA germline mutation, largely consisting of immunohistochemical markers independent of clinical characteristics. This may improve identification of potential BRCA germline mutation carriers and optimize referral for germline mutation testing.

BRCA Mutation Status to Personalize Management of Recurrent Ovarian Cancer: A Multicenter Study.

The aim of this study was to assess the correlation between BRCA mutation status and disease presentation, treatment strategy, and survival in a multicenter series of recurrent high-grade serous ovarian cancer (HGSOC) women. A consecutive series of recurrent HGSOC patients with partially or fully platinum-sensitive disease admitted to the Gynecologic Oncology Units of the Catholic University of the Sacred Heart and Sapienza University of Rome. Main eligibility criteria were known BRCA 1/2 germline mutation status and a minimum follow-up period from recurrence of at least 6months. Overall, 126 patients met the eligibility criteria, of whom 76 (60%) were BRCA wild-type (BRCAwt) and 50 (40%) were BRCA 1/2 germline mutation carriers (BRCAmut). Among the latter, 37 (74%) patients presented with BRCA1 mutation, and 13 (26%) presented with BRCA2. No differences were found regarding patterns of disease presentation between BRCAwt and BRCAmut women. BRCAmut patients had the best post-recurrence survival (PRS) regardless of having received secondary cytoreductive surgery (SCS) or not, with a 5-year PRS of 73% in non-resected women versus 78% in resected women (p = 0.558). Conversely, BRCAwt patients who underwent complete SCS had a significantly longer PRS compared with BRCAwt patients who did not receive surgery (5-year PRS of 54% vs. 42%; p = 0.048). Recurrent ovarian cancer BRCAmut patients have the best prognosis regardless of SCS, whereas PRS in BRCAwt women can improve when complete SCS is performed. The identification and incorporation of predictive biomarkers such as BRCA status to tailor the medical and surgical approach is paramount to the success of recurrent HGSOC treatments.

Frequency of Germline Mutations in Cancer Susceptibility Genes in Malignant Mesothelioma.

The aim of the current study was to determine the prevalence and clinical predictors of germline cancer susceptibility mutations in patients with malignant mesothelioma (MM). We performed targeted capture and next-generation sequencing of 85 cancer susceptibility genes on germline DNA from 198 patients with pleural, peritoneal, and tunica vaginalis MM. Twenty-four germline mutations were identified in 13 genes in 23 (12%) of 198 patients. BAP1 mutations were the most common (n = 6; 25%). The remaining were in genes involved in DNA damage sensing and repair (n = 14), oxygen sensing (n = 2), endosome trafficking (n = 1), and cell growth (n = 1). Pleural site (odds ratio [OR], 0.23; 95% CI, 0.10 to 0.58; P < .01), asbestos exposure (OR, 0.28; 95% CI, 0.11 to 0.72; P < .01), and older age (OR, 0.95; 95% CI, 0.92 to 0.99; P = .01) were associated with decreased odds of carrying a germline mutation, whereas having a second cancer diagnosis (OR, 3.33; 95% CI, 1.22 to 9.07; P = .02) significantly increased the odds. The odds of carrying a mutation in BAP1 (OR, 1,658; 95% CI, 199 to 76,224; P < .001), BRCA2 (OR, 5; 95% CI, 1.0 to 14.7; P = .03), CDKN2A (OR, 53; 95% CI, 6 to 249; P < .001), TMEM127 (OR, 88; 95% CI, 1.7 to 1,105; P = .01), VHL (OR, 51; 95% CI, 1.1 to 453; P = .02), and WT1 (OR, 20; 95% CI, 0.5 to 135; P = .049) were significantly higher in MM cases than in a noncancer control population. Tumor sequencing identified mutations in a homologous recombination pathway gene in 52% (n = 29 of 54). A significant proportion of patients with MM carry germline mutations in cancer susceptibility genes, especially those with peritoneal MM, minimal asbestos exposure, young age, and a second cancer diagnosis. These data support clinical germline genetic testing for patients with MM and provide a rationale for additional investigation of the homologous recombination pathway in MM.