Deleterious Germline Mutations Research Articles

Validating Risk Prediction Models for Multiple Primaries and Competing Cancer Outcomes in Families With Li-Fraumeni Syndrome Using Clinically Ascertained Data.

There exists a barrier between developing and disseminating risk prediction models in clinical settings. We hypothesize that this barrier may be lifted by demonstrating the utility of these models using incomplete data that are collected in real clinical sessions, as compared with the commonly used research cohorts that are meticulously collected. Genetic counselors (GCs) collect family history when patients (ie, probands) come to MD Anderson Cancer Center for risk assessment of Li-Fraumeni syndrome, a genetic disorder characterized by deleterious germline mutations in the TP53 gene. Our clinical counseling-based (CCB) cohort consists of 3,297 individuals across 124 families (522 cases of single primary cancer and 125 cases of multiple primary cancers). We applied our software suite LFSPRO to make risk predictions and assessed performance in discrimination using AUC and in calibration using observed/expected (O/E) ratio. For prediction of deleterious TP53 mutations, we achieved an AUC of 0.78 (95% CI, 0.71 to 0.85) and an O/E ratio of 1.66 (95% CI, 1.53 to 1.80). Using the LFSPRO.MPC model to predict the onset of the second cancer, we obtained an AUC of 0.70 (95% CI, 0.58 to 0.82). Using the LFSPRO.CS model to predict the onset of different cancer types as the first primary, we achieved AUCs between 0.70 and 0.83 for sarcoma, breast cancer, or other cancers combined. We describe a study that fills in the critical gap in knowledge for the utility of risk prediction models. Using a CCB cohort, our previously validated models have demonstrated good performance and outperformed the standard clinical criteria. Our study suggests that better risk counseling may be achieved by GCs using these already-developed mathematical models.

Immunohistochemical findings and clinicopathological features of breast cancers with pathogenic germline mutations in Non-BRCA genes

Deleterious germline mutations in multiple genes confer an increased breast cancer (BC) risk. Immunohistochemical (IHC) expression of protein products of mutated high-risk genes has not been investigated in BC. We hypothesized that pathogenic mutations may lead to an abnormal IHC expression pattern in the tumor cells. BCs with deleterious germline mutations in CHEK2, ATM, PALB2 &PTEN were identified. Immunohistochemistry was performed using Dako staining platform on formalin fixed paraffin embedded tumor tissue. Primary antibodies for PALB2 (ab202970), ATM [2C1(1A10)}, CHK2 (EPR4325), and PTEN (138G6) proteins were used for BCs with respective deleterious mutations. IHC expression was assessed in tumor and adjacent benign breast tissue. Total 27 BCs with 10 CHEK2, 9 ATM, 6 PALB2 & 2 PTEN deleterious germline mutations were identified. IHC staining was performed on 8 CHEK2, 7 ATM, 6 PALB2 & 2 PTEN cases. Abnormal CHEK2 IHC staining was identified in 7/8(88%) BCs. Three distinct CHK2 IHC patterns were noted: 1) Strong diffuse nuclear positivity (5 BC), 2) Null-pattern (2 BC), & 3) Normal breast–like staining in 1 BC Four of 5 (80%) strong CHK2 staining BC had missense CHEK2 mutations. Null-pattern was present with a missense & a frameshift mutation. Normal breast-like CHEK2 IHC staining pattern was present in 1 BC with CHEK2 frameshift mutation. Loss of nuclear/cytoplasmic PTEN IHC expression was noted in 2 in-situ carcinomas. Abnormal PTEN and CHK2 IHC were present in atypical ductal hyperplasia and flat epithelial atypia. ATM and PALB2 IHC expression patterns were similar in tumor cells and benign breast epithelium: mild to moderate intensity nuclear and cytoplasmic staining. We report abnormal CHEK2 IHC expression in 88% of BCs with pathogenic CHEK2 mutations. With PTEN and CHEK2 pathogenic mutations, abnormal IHC patterns are seen in early atypical proliferative lesions. IHC may be applied to identify CHEK2 &PTEN mutated BCs and precursor lesions.

Characteristics of germline DNA damage response gene mutations in ovarian cancer in Southwest China

DNA damage response (DDR) pathways are responsible for repairing endogenous or exogenous DNA damage to maintain the stability of the cellular genome, including homologous recombination repair (HRR) pathway, mismatch repair (MMR) pathway, etc. In ovarian cancer, current studies are focused on HRR genes, especially BRCA1/2, and the results show regional and population differences. To characterize germline mutations in DDR genes in ovarian cancer in Southwest China, 432 unselected ovarian cancer patients underwent multi-gene panel testing from October 2016 to October 2020. Overall, deleterious germline mutations in DDR genes were detected in 346 patients (80.1%), and in BRCA1/2 were detected in 126 patients (29.2%). The prevalence of deleterious germline mutations in BRCA2 is higher than in other studies (patients are mainly from Eastern China), and so is the mismatch repair genes. We identified three novel BRCA1/2 mutations, two of which probably deleterious (BRCA1 p.K1622* and BRCA2 p.L2987P). Furthermore, we pointed out that deleterious mutations of FNACD2 and RECQL4 are potential ovarian cancer susceptibility genes and may predispose carriers to ovarian cancer. In conclusion, our study highlights the necessity of comprehensive germline mutation detection of DNA damage response genes in ovarian cancer patients, which is conducive to patient management and genetic counseling.

LFSPROShiny: An Interactive R/Shiny App for Prediction and Visualization of Cancer Risks in Families With Deleterious Germline TP53 Mutations.

LFSPRO is an R library that implements risk prediction models for Li-Fraumeni syndrome (LFS), a genetic disorder characterized by deleterious germline mutations in the TP53 gene. To facilitate the use of these models in clinics, we developed LFSPROShiny, an interactive R/Shiny interface of LFSPRO that allows genetic counselors (GCs) to perform risk predictions without any programming components and further visualize the risk profiles of their patients to aid the decision-making process. LFSPROShiny implements two models that have been validated on multiple LFS patient cohorts: a competing risk model that predicts cancer-specific risks for the first primary and a recurrent-event model that predicts the risk of a second primary tumor. Starting with a visualization template, we keep regular contact with GCs, who ran LFSPROShiny in their counseling sessions, to collect feedback and discuss potential improvement. On receiving the family history as input, LFSPROShiny renders the family into a pedigree and displays the risk estimates of the family members in a tabular format. The software offers interactive overlaid side-by-side bar charts for visualization of the patients' cancer risks relative to the general population. We walk through a detailed example to illustrate how GCs can run LFSPROShiny in clinics from data preparation to downstream analyses and interpretation of results with an emphasis on the utilities that LFSPROShiny provides to aid decision making. Since December 2021, we have applied LFSPROShiny to over 100 families from counseling sessions at the MD Anderson Cancer Center. Our study suggests that software tools with easy-to-use interfaces are crucial for the dissemination of risk prediction models in clinical settings, hence serving as a guideline for future development of similar models.

Mainstream Model of Genetic Testing for Prostate Cancer at a Large Tertiary Cancer Centre

BackgroundAn estimated 20% to 30% of men with advanced prostate cancer carry a mutation in DNA damage repair genes, of which half are estimated to be germline. Eligibility criteria for germline genetic testing expanded significantly for Ontario patients in May 2021 and many centers adopted a “mainstream” model, defined as oncologist-initiated genetic testing. MethodsWe conducted a retrospective chart review to report on the first-year mainstream experience of a large tertiary oncologic center, the Sunnybrook Odette Cancer Centre. All patients who underwent mainstream at the discretion of their treating physician were included. A subset underwent somatic profiling as part of clinical trial screening. Descriptive statistics were used to report baseline clinicopathologic characteristics and treatments received. ResultsBetween May 1, 2021, and May 30, 2022, 174 patients with prostate cancer underwent mainstream germline genetic testing with a 19-gene panel. Median age was 75 (IQR 68-80), and 82% of patients were diagnosed with either de novo metastatic or high-risk localized prostate adenocarcinoma. Fourteen patients (8%; 95% CI 4%-12%) were found to have a deleterious germline mutation, including pathogenic or likely pathogenic variants in BRCA1/2, ATM, CHEK2, PMS2, RAD51C, HOXB13, and BRIP1. Forty-nine patients (28%; 95% CI 21%-35%) were found to have a variant of uncertain significance. Thirty-four patients also had next-generation sequencing (NGS) of their somatic tissue. Among this subset, 8 of 34 (23%) had an alteration in homologous recombination repair (HRR) genes. Of the 14 patients with a germline mutation, none had a prior personal history of malignancy and 6 (43%) did not have any first- or second-degree relatives with history of prostate, pancreatic, breast, or ovarian cancer. ConclusionWe report on the real-world characteristics of prostate cancer patients who underwent mainstream germline genetic testing. Personal history and family history of cancer cannot reliably stratify patients for the presence of pathogenic germline variants.

Abstract B138: Pharmacodynamics-driven phase 2 trial of talazoparib in patients with advanced solid tumors and aberrations in genes involved in DNA damage response

Abstract Background: Talazoparib is a poly (ADP-ribose) polymerase inhibitor (PARPi) with increased trapping of PARP-DNA complexes compared to other PARPi in clinical development. Talazoparib has single-agent synthetic lethality in BRCA1/2- and PTEN-deficient cell lines, has potent antitumor activity in animal models of tumors harboring mutations in DNA repair pathways, and has FDA-approved indications in advanced BRCA-mutated and HER2-negative breast cancer and in homologous recombination repair gene-mutated metastatic castration-resistant prostate cancer in combination with enzalutamide. This pilot study evaluated the pharmacodynamic (PD) effects of talazoparib on DNA damage response (DDR) markers in tumor biopsy tissue in both patients (pts) who are PARPi-naïve and pts who have received prior PARPi other than talazoparib to investigate for potential differential PARPi PD responses in DNA replication stress. Methods: We are conducting a multicenter phase 2 trial in adult pts with eligible deleterious germline or somatic mutations in BRCA1/2 or genes involved in DDR including ATM, ARID1A, IDH1, BAP1, ATR, CHK2, and PALB2. Pts were enrolled and assessed in two cohorts: 1) pts who were PARPi-naïve, and 2) pts who were treated with and had documented progression on a PARPi other than talazoparib. Talazoparib is administered orally at a dose of 1000 µg/day (D) in 28 D cycles (C). The primary objective is determining the replication stress PD effect of talazoparib as evaluated by activation of Rad51 combined with a lack of γH2AX activation. Paired tumor biopsies (baseline and C2D1) will be analyzed for DDR markers (γH2AX, pNBS1, and Rad51) by IFA. Responses and adverse events (AEs) are defined by RECIST 1.1 and CTCAE v5.0, respectively. Results: The PARPi-naïve cohort had 15 pts enrolled with a median age of 58 years (range 38-76) and median prior lines of systemic therapy of 2 (range 1-5). The PARPi-treated cohort had 8 pts enrolled with a median age of 72 years (range 35-85) and median prior lines of systemic treatment of 5.5 (range 1-10). A total of 11 sets of pre-treatment and post-treatment tumor biopsies have been received to date and analyses of DDR markers are ongoing. Of 11 pts in the PARPi-naïve cohort evaluable for response, 6 pts had stable disease (SD) as best response with 2 pts (nasal cavity cancer with ARID1A alteration, bile duct cancer with IDH1 alteration) who received talazoparib for ≥ 6 C. Of 7 pts in the PARPi-treated cohort evaluable for response, 4 pts had SD as best response. Treatment-related AEs of ≥ grade 2 with ≥ 5% incidence included anemia (n=10, 43.5%), leukopenia (n=7, 30.4%), lymphopenia (n=6, 26.1%), thrombocytopenia (n=6, 26.1%), and neutropenia (n=4, 17.4%). Conclusions: Study enrollment and analyses of PD DDR markers in paired tumor biopsies are both ongoing with data to be presented at the conference. No responses have been observed to date, which may be due to prior therapies, tumor histologies, mutational selection or dose delivered with further characterization anticipated via PD DDR marker data. Citation Format: Brian Ko, Geraldine H O'Sullivan Coyne, Abdul Rafeh Naqash, Thomas J George, David DeRemer, Larry Rubinstein, Jennifer Zlott, Deborah Wilsker, Donna Ketchum, Stephanie Runkle, Katherine V Ferry-Galow, Ralph E Parchment, Naoko Takebe, Sarah Shin, Andrea R Voth, Jiuping Ji, S. Percy Ivy, James H Doroshow, Alice P Chen. Pharmacodynamics-driven phase 2 trial of talazoparib in patients with advanced solid tumors and aberrations in genes involved in DNA damage response [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B138.

Carboplatin in Patients With Metastatic Castration-Resistant Prostate Cancer Harboring Somatic or Germline Homologous Recombination Repair Gene Mutations: Phase II Single-Arm Trial.

Approximately 20%-25% of patients with metastatic castration-resistant prostate cancer (mCRPC) harbor a deleterious germline or somatic mutation in the homologous recombination repair (HRR) pathway genes, which is involved in the repair of double-stranded DNA damage. Half of these mutations are germline, while the remaining are exclusively somatic. While polyadenosine 5'diphosphoribose [poly (ADP-ribose)] polymerase inhibitors, such as olaparib and rucaparib, are effective in this subgroup, their widespread use is limited due to the associated high cost, especially in resource-constrained settings. Notably, platinum agents like carboplatin have exquisite sensitivity to cells with defective DNA repair machinery. Carboplatin, a conventional, inexpensive chemotherapeutic agent, offers a potential alternative treatment in such patients. Several retrospective small case series support this hypothesis. However, there are no prospective clinical trials of carboplatin in patients with mCRPC with HRR mutations. The primary objective is to assess the objective response rate of 3 weekly carboplatin treatments in patients with mCRPC harboring deleterious mutations in the HRR pathway genes and previously treated with a taxane or a novel antiandrogen agent. The secondary objectives include progression-free survival, health-related quality of life, and safety profile of carboplatin. Patients diagnosed with mCRPC harboring HRR pathway mutations previously treated with docetaxel or novel antiandrogen agents (abiraterone, enzalutamide, apalutamide, or darolutamide) or both will be eligible. Genes involved directly or indirectly in the HRR pathway will be tested. In this single-arm phase II study, we will screen approximately 200 patients to enroll 49 patients, and carboplatin (dosing at the area under curve=5) will be administered every 3 weeks until progression or intolerable side effects. The primary end point will be assessed as the proportion of patients with a reduction of serum prostate-specific antigen by more than 50% from enrollment. Secondary outcomes include progression-free survival-soft-tissue disease progression (by response evaluation criteria in solid tumors, version 1.1, and bone lesion progression using Prostate Cancer Clinical Trials Working Group 3 criteria), health-related quality of life during carboplatin treatment using the Functional Assessment of Cancer Therapy-Prostate questionnaire and the European Organisation for Research and Treatment of Cancer questionnaire and safety profile of carboplatin (National Cancer Institute's Common Terminology Criteria for Adverse Events version 5.0). The trial started enrollment in September 2023. This trial is ongoing, and 12 patients have been recruited to date. All 49 participants will be enrolled according to plan. This prospective phase II trial represents a critical step toward addressing the therapeutic gap in patients with mCRPC harboring HRR pathway mutations, particularly in demographic regions with limited access to poly (ADP-ribose) polymerase inhibitors. Outcomes from this study will inform clinical practice and guide future phase III randomized trials, ultimately improving patient outcomes globally. Clinical Trials Registry of India CTRI/2023/04/051507; https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=Njc0NjU=&Enc=&userName=. DERR1-10.2196/54086.

The Landscape of BRCA Mutations among Egyptian Women with Breast Cancer.

Deleterious germline mutations in BRCA1 and BRCA2 genes are associated with a high risk of breast and ovarian cancer. In many developing countries, including Egypt, the prevalence of BRCA1/2 mutations amongwomen with breast cancer (BC) is unknown. We aimed to determine the prevalence of deleterious germline BRCA mutations in Egyptian patients with breast cancer. We report the results of a cohort study of 81 Egyptian patients with breast cancer who were tested for germline BRCA1/2 mutations during routine clinical practice, mostly for their young age of presentation, BC subtype, or presence of family history. In addition, we searched five databases to retrieve studies that reported the prevalence of BRCA1/2 mutation status in Egyptian women with BC. A systematic review of the literature was performed, including prospective and retrospective studies. In our patient cohort study, 12 patients (14.8%) were positive for either BRCA1/2 deleterious mutations. Moreover, 13 (16.1%) patients had a variant of unknown significance (VUS) of BRCA1/2 genes. Twelve studies were eligible for the systematic review, including 610 patients. A total of 19 deleterious germline mutations in BRCA1/2 were identified. The pooled prevalence of BRCA1/2 mutations was 40% (95% confidence interval 1-80%). The reported prevalence was highly variable among the small-sized published studies that adopted adequate techniques. In our patient cohort, there was a high incidence of VUS in BRCA1/2 genes. Accordingly, there is an actual demand to conduct a prospective well-designed national study to accurately estimate the prevalence of BRCA1/2 mutations among patients with BC in Egypt.

Combining next-generation hormonal therapy with PARP inhibition in metastatic castration-resistant prostate cancer

In a paradigm of precision oncology, elegant preclinical work showed that inhibition of poly(ADP-ribose) polymerase (PARP) proteins can exploit a deficiency of cancer cells to repair DNA double-strand breaks through homologous recombination repair (HRR), 1 Lord CJ Ashworth A PARP inhibitors: synthetic lethality in the clinic. Science. 2017; 355: 1152-1158 Crossref PubMed Scopus (1411) Google Scholar and the resulting synthetic lethality was first shown to be clinically effective in ovarian cancer carrying a germline deleterious mutation in BRCA1 or BRCA2, key HRR genes. 2 Banerjee S Moore KN Colombo N et al. Maintenance olaparib for patients with newly diagnosed advanced ovarian cancer and a BRCA mutation (SOLO1/GOG 3004): 5-year follow-up of a randomised, double-blind, placebo-controlled, phase 3 trial. Lancet Oncol. 2021; 22: 1721-1731 Summary Full Text Full Text PDF PubMed Scopus (92) Google Scholar For prostate cancer, the discovery of alterations in BRCA2 and other HRR-related genes in up to 20% of advanced disease 3 Robinson D Van Allen EM Wu YM et al. Integrative clinical genomics of advanced prostate cancer. Cell. 2015; 161: 1215-1228 Summary Full Text Full Text PDF PubMed Scopus (2077) Google Scholar led to the development of several biomarker-driven trials of PARP inhibitors in patients with metastatic castration-resistant prostate cancer (mCRPC) 4 Abida W Patnaik A Campbell D et al. Rucaparib in men with metastatic castration-resistant prostate cancer harboring a BRCA1 or BRCA2 gene alteration. J Clin Oncol. 2020; 38: 3763-3772 Crossref PubMed Scopus (309) Google Scholar , 5 de Bono JS Mehra N Scagliotti GV et al. Talazoparib monotherapy in metastatic castration-resistant prostate cancer with DNA repair alterations (TALAPRO-1): an open-label, phase 2 trial. Lancet Oncol. 2021; 22: 1250-1264 Summary Full Text Full Text PDF PubMed Scopus (79) Google Scholar , 6 Hussain M Mateo J Fizazi K et al. Survival with olaparib in metastatic castration-resistant prostate cancer. N Engl J Med. 2020; 383: 2345-2357 Crossref PubMed Scopus (289) Google Scholar , 7 Smith MR Scher HI Sandhu S et al. Niraparib in patients with metastatic castration-resistant prostate cancer and DNA repair gene defects (GALAHAD): a multicentre, open-label, phase 2 trial. Lancet Oncol. 2022; 23: 362-373 Summary Full Text Full Text PDF PubMed Scopus (41) Google Scholar and to the regulatory approval of rucaparib and olaparib as monotherapy for the treatment of mCRPC harbouring mutations in BRCA2 and other HRR genes. Talazoparib plus enzalutamide in men with first-line metastatic castration-resistant prostate cancer (TALAPRO-2): a randomised, placebo-controlled, phase 3 trialTalazoparib plus enzalutamide resulted in clinically meaningful and statistically significant improvement in rPFS versus standard of care enzalutamide as first-line treatment for patients with mCRPC. Final overall survival data and additional long-term safety follow-up will further clarify the clinical benefit of the treatment combination in patients with and without tumour HRR gene alterations. Full-Text PDF

Prevalence of germline mutations in women with breast and/or ovarian cancer in a tertiary care center in Pune, India

In India, the incidence of breast cancer accounted for 1,78,361 cases, whereas ovarian cancer accounts for 45,701 cases, according to Globocan Report 2020. These cancers are known to have a hereditary basis, and >10% of them are associated with pathogenic BRCA1 and BRCA2 mutations. The prevalence of BRCA1 and BRCA2 varies across various Indian studies and is reported to be 2.9–28%. However, gene mutations other than BRCA1 and BRCA2 which are shown to increase the risk of hereditary breast and ovarian cancer (HBOC) are underreported. Objectives: The objective of this study was to estimate the prevalence of deleterious germline mutations among women with breast and/or ovarian cancer. Material and Methods: A cross-sectional study was conducted in the department of oncology at a super specialty hospital. Patients were enrolled based on the current National Comprehensive Cancer Network guidelines for genetic risk and evaluation of HBOC. Demographic and clinical information was extracted from the electronic medical records of the hospitals from 2018 to 2021. Next-generation sequencing (NGS) was performed on the extracted DNA using a custom capture kit and classified based on the American College of Medical Genetics. Results: A total of 94 patients suspected of having HBOC were examined for deleterious germline mutations. The median age of the patient was 46 years (range: 38–57 years). Breast and ovarian cancer patients constituted 64.9% and 35.1%, respectively. The overall mutation detection rate was 25.5%. The positive mutation detection rate was 26.2% and 24.2% in breast and ovarian cancer, respectively, whereas the variant of uncertain significance rate was 18.03% and 24.2%, respectively. Among the pathogenic mutations, BRCA1 was the most common mutation in women with breast cancer (81.3%). In ovarian cancer, it was 50%. BRCA2 mutation was more prevalent in ovarian cancer (50%). Conclusion: Our study reports a higher prevalence of germline BRCA1 and BRCA2 mutations in breast and ovarian cancer as compared to other studies. Genetic testing can be offered to high-risk women regardless of family history. This will be useful during diagnosis and help physicians in planning subsequent treatment.

Comprehensive genomic landscape in pancreatic cancer using whole-exome sequencing.

e16307 Background: Pancreatic ductal adenocarcinoma is one of the fatal malignancies in the world, mostly as a result of the absence of early detection and specific treatment solutions. Consequently, identifying mutational profiles and molecular biomarker are essential for increasing the viability of precision therapy for pancreatic cancer. Methods: We gathered blood and tumour tissue samples from 47 Chinese pancreatic cancer patients and used whole-exome sequencing (WES) to evaluate the genetic landscape. Results: Our results showed the most frequently somatic alteration genes were KRAS (74.5%), TP53 (51.1%), SMAD4 (17%), ARID1A (12.8%), CDKN2A (12.8%), TENM4 (10.6%), TTN (8.5%), RNF43 (8.5%), FLG (8.5%) and GAS6 (6.4%) in Chinese pancreatic ductal adenocarcinoma patients. We also found that three deleterious germline mutations ( ATM c.4852C > T/p. R1618*, WRN c.1105C > T/p. R369*, PALB2 c.2760dupA/p. Q921Tfs*7) and two novel fusions ( BRCA1-RPRML, MIR943 (intergenic)- FGFR3). When compared to the Cancer Genome Atlas (TCGA) database, there is a greater mutation frequency of TENM4 (10.6% vs. 1.6%, p= 0.01), GAS6 (6.4% vs. 0.5%, p= 0.035), MMP17 (6.4% vs. 0.5%, p= 0.035), ITM2B (6.4% vs. 0.5%, p= 0.035) and USP7 (6.4% vs. 0.5%, p= 0.035) as well as a reduced mutation frequency of SMAD4 (17.0% vs. 31.5%, p= 0.075) and CDKN2A (12.8% vs. 47.3%, p< 0.001) were observed in the Chinese cohort. Among the 41 individual examined for PD-L1 expression, 15 (36.6%) had positive PD-L1 expression. The median tumour mutational burden (TMB) was found to be 12 muts (range, 0-124). The TMB index was higher in patients with mutant-type KRAS MUT/ TP53 MUT ( p< 0.001), CDKN2A ( p= 0.547), or SMAD4 ( p= 0.064) compared to patients with wild-type KRAS/ TP53, CDKN2A, or SMAD4. Conclusions: We exhibited real-world genetic traits and new alterations in Chinese individuals with cancer of pancreas, which might have interesting implications for future individualized therapy and medication development.

Mutational landscape of intracranial germ cell tumors.

e14060 Background: Intracranial germ cell tumours (GCTs) are relatively rare tumours of the central nervous system, which account for 1% to 3% of cases. The pathogenesis of intracranial GCTs is unknown, molecular diagnostic methods currently play only a minor role in the diagnosis of CNS germ cell tumours, which generally rest on histopathological and secretory features. The objective of this study was to explore the molecular profile associated with Chinese intracranial GCT patients. Methods: This study retrospectively analyzed the genomic features of 24 intracranial GCT patients. Next-generation sequencing (NGS) of 551-gene panel was performed to detect gene mutations in tumor and blood samples of the patients. Results: The tumors originated most frequently in the pineal region (41.6%, 10/24), followed by the sellar tumor (16.6%, 4/24). The average age of the patients was 14 years (range, 4-55years), There is a male preponderance of 2:1. The most common mutation genes were KIT (4.23%, n=6), KRAS (2.82%, n=4) and PTEN (2.11%, n=3). KIT mutations are mainly missense mutations concentrated in exon 17, exon 11 and exon 13. Exon 2 and exon 3 of KRAS gene were the main mutation hotspots, mainly G12X(2.08%) missense mutation. The co-mutation of KIT and KRAS was only in one patient. Unexpectedly, four patients (16.6%) carried germline deleterious mutations, in FANCA(n=1), FANCD2(n=1), FANCE(n=1), SDHA(n=1). Two of the patients with germline mutations co-mutated with KIT and KRAS, respectively. Conclusions: 16.6% of the intracranial GCT patients carry germline deleterious mutations, and 12.5% in Fanconi anemia (FA) gene. Overall, these findings indicate that the Fanconi anemia (FA) pathway and the PI3K/AKT pathway play a significant role in intracranial GCTs tumorigenesis.

Clinical and genetic characteristics in pancreatic cancer from Chinese patients revealed by whole exome sequencing.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies worldwide, mostly as a result of the absence of early detection and specific treatment solutions. Consequently, identifying mutational profiles and molecular biomarkers is essential for increasing the viability of precision therapy for pancreatic cancer. We collected blood and tumor tissue samples from 47 Chinese pancreatic cancer patients and used whole-exome sequencing (WES) to evaluate the genetic landscape. Our results showed the most frequently somatic alteration genes were KRAS (74.5%), TP53(51.1%), SMAD4 (17%), ARID1A (12.8%), CDKN2A (12.8%), TENM4 (10.6%), TTN (8.5%), RNF43(8.5%), FLG (8.5%) and GAS6 (6.4%) in Chinese PDAC patients. We also found that three deleterious germline mutations (ATM c.4852C>T/p. R1618*, WRN c.1105C>T/p. R369*, PALB2 c.2760dupA/p. Q921Tfs*7) and two novel fusions (BRCA1-RPRML, MIR943 (intergenic)-FGFR3). When compared to the Cancer Genome Atlas (TCGA) database, there is a greater mutation frequency of TENM4 (10.6% vs. 1.6%, p = 0.01), GAS6(6.4% vs. 0.5%, p = 0.035), MMP17(6.4% vs. 0.5%, p = 0.035), ITM2B (6.4% vs. 0.5%, p = 0.035) and USP7 (6.4% vs. 0.5%, p= 0.035) as well as a reduced mutation frequency of SMAD4 (17.0% vs. 31.5%, p = 0.075) and CDKN2A (12.8% vs. 47.3%, p < 0.001) were observed in the Chinese cohort. Among the 41 individuals examined for programmed cell death ligand 1(PD-L1) expression, 15 (36.6%) had positive PD-L1 expression. The median tumor mutational burden (TMB) was found to be 12muts (range, 0124). The TMB index was higher in patients with mutant-type KRAS MUT/TP53 MUT (p < 0.001), CDKN2A (p = 0.547), or SMAD4 (p = 0.064) compared to patients with wild-type KRAS/TP53, CDKN2A, or SMAD4. We exhibited real-world genetic traits and new alterations in Chinese individuals with cancer of the pancreas, which might have interesting implications for future individualized therapy and medication development.

Practical Utility of Liquid Biopsies for Evaluating Genomic Alterations in Castration-Resistant Prostate Cancer.

Traditional tissue-based assessments of genomic alterations in castration-resistant prostate cancer (CRPC) can be challenging. To evaluate the real-world clinical utility of liquid biopsies for the evaluation of genomic alterations in CRPC, we preemptively collected available plasma samples and archival tissue samples from patients that were being treated for clinically confirmed CRPC. The cell-free DNA (cfDNA) and tumor tissue DNA were analyzed using the AlphaLiquid®100-HRR panel. Plasma samples from a total of 87 patients were included in this study. Somatic mutations from cfDNA were detected in 78 (89.7%) patients, regardless of the presence of overt metastasis or concomitant treatment given at the time of plasma sample collection. Twenty-three patients were found to have known deleterious somatic or germline mutations in HRR genes from their cfDNA. Archival tissue samples from 33 (37.9%) patients were available for comparative analysis. Tissue sequencing was able to yield an NGS result in only 51.5% of the tissue samples. The general sensitivity of cfDNA for detecting somatic mutations in tissues was 71.8%, but important somatic/germline mutations in HRR genes were found to have a higher concordance (100%). Liquid biopsies can be a reasonable substitute for tissue biopsies in CRPC patients when evaluating genomic alterations.

Incidence and Prognostic Impact of Deleterious Germline Mutations in Primary Advanced Ovarian Carcinoma Patients.

Data on deleterious variants in genes other than BRCA1/2 remain limited. A retrospective cohort study was performed, including primary OC cases with TruRisk® germline gene panel testing between 2011 and 2020. Patients with testing after relapse were excluded. The cohort was divided into three groups: (A) no mutations, (B) deleterious BRCA1/2 mutations, and (C) deleterious mutations in other genes. A total of 702 patients met the inclusion criteria. Of these 17.4% (n = 122) showed BRCA1/2 mutations and a further 6.0% (n = 42) in other genes. Three-year overall survival (OS) of the entire cohort was significantly longer in patients with germline mutations (85%/82.8% for cohort B/C vs. 70.2% for cohort A, p < 0.001) and 3-year progression-free survival (PFS) only for cohort B (58.1% vs. 36.9%/41.6% in cohort A/C, p = 0.002). In multivariate analysis for the subgroup of advanced-stages of high-grade serous OC, both cohorts B/C were found to be independent factors for significantly better outcome, cohort C for OS (HR 0.46; 95% CI 0.25-0.84), and cohort B for both OS and PFS (HR 0.40; 95% CI 0.27-0.61 and HR 0.49; 95% CI 0.37-0.66, respectively). Germline mutations were detected in a quarter of OC patients, and a quarter of those in genes other than BRCA1/2. Germline mutations demonstrate in our cohort a prognostic factor and predict better prognosis for OC patients.

Patients with deleterious germline mutations: A heterogeneous population for pancreatic cancer screening?

Modest data exist on the benefits of screening and surveillance for pancreatic cancer (PC) in high-risk individuals. Intraductal papillary mucinous neoplasms (IPMN) are known precursors to PC. We hypothesized that patients with high-risk deleterious germline mutations have a higher prevalence of IPMN. All patients undergoing prospective screening at a single institution from 2013 to 2019 were reviewed. Of 1166 patients screened, 358 (31%) possessed germline mutations and/or family history of PC (mutations n = 201/358, 56%, family history n = 226/358, 63%) (median follow-up 2.7 years). IPMN was found in 127 patients (35.5%). The prevalence of IPMN in mutation carriers (18%) was higher than in the general population (p < 0.01). Germline mutation was an independent predictor of IPMN (odds ratio [OR] = 3.2; p < 0.01), while family history was not (p = 0.22). IPMN prevalence was distributed unevenly between mutation types (67%-Peutz-Jeghers; 43%-HNPCC, 24%-BRCA2; 17%-ATM; 9%-BRCA1; 0%-CDKN2A and PALB2). In this series, 18% of mutation carriers harbored IPMN, higher than the general population. Germline mutation, but not a family history of PC, was independently associated with IPMN. This prevalence varied across mutation subtypes, suggesting not all mutation carriers develop precancerous lesions. Genetic testing for patients with a positive family history may improve screening modalities for this high-risk population.

BRCA1 and BRCA2 germline mutation analysis from a cohort of 1267 patients at high risk for breast cancer in Brazil

We determined the frequency and mutational spectrum of BRCA1 and BRCA2 in a series of patients at high risk for developing breast cancer from Brazil. A total of 1267 patients were referred for BRCA genetic testing, and no obligation of fulfilling criteria of mutation probability methods for molecular screening was applied. Germline deleterious mutations in BRCA1/2 (i.e., pathogenic/likely pathogenic variants) were identified in 156 out of 1267 patients (12%). We confirm recurrent mutations in BRCA1/2, but we also report three novel mutations in BRCA2, not previously reported in any public databases or other studies. Variants of unknown significance (VUS) represent only 2% in this dataset and most of them were detected in BRCA2. The overall mutation prevalence in BRCA1/2 was higher in patients diagnosed with cancer at age > 35years old, and with family history of cancer. The present data expand our knowledge of BRCA1/2 germline mutational spectrum, and it is a valuable clinical resource for genetic counseling and cancer management programs in the country.

Implementing HRD Testing in Routine Clinical Practice on Patients with Primary High-Grade Advanced Ovarian Cancer.

The chemotherapy backbone for patients with high-grade advanced epithelial ovarian cancer (HG-AOC) is carboplatin and paclitaxel followed by a maintenance therapy either with bevacizumab, with a PARP inhibitor, or with a combination of both, which is defined by the presence of a homologous recombination deficiency (HRD) and by the BRCA1/2 status. This study included patients with a primary diagnosis of HG-AOC treated between December 2019 and December 2021. The HRD status was measured using the Myriad myChoice® test on all the patients with an indication for tumor HRD testing. Germline testing was conducted on all the patients using the TruRisk® panel as recommended by the national guidelines. HRD testing was requested for 190 patients, and, for 163 patients (85.8%), an HRD test result was available. An HRD test result could not be reported in 27 patients due to an insufficient tumor yield. The median time that it took to receive the HRD test results was 37 days (range of 8-97). In total, an HRD was present in 44.7% (73/163) of the patients based on a GIS ≥ 42 in 42.9% of the patients and based on a tumor BRCA1/2 mutation in 3 cases (all with a GIS < 42). The germline testing results were available for 148 patients, and, in 18 patients (12.2%), a deleterious germline mutation was detected. Of the 27 patients without sufficient HRD testing, BRCA1/2 germline testing results were available for 19 patients (70.4%), and a deleterious germline mutation was detected in 2 patients (7.4%). The implementation of HRD testing is feasible, and the results become available for treatment decisions in a timely manner for most patients. The prerequisite for HRD testing with the Myriad myChoice® test is a sufficient amount of tumor tissue. The cotesting of HRD and BRCA1/2 germline testing should be aimed for in order to enable optimal and timely treatment decisions on maintenance therapy as well as to test patients on whom the HRD test will not be evaluable.

Frequency of Pathogenic Germline Mutations in Early and Late Onset Familial Breast Cancer Patients Using Multi-Gene Panel Sequencing: An Egyptian Study.

Precision oncology has been increasingly used in clinical practice and rapidly evolving in the oncology field. Thus, this study was performed to assess the frequency of germline mutations in early and late onset familial breast cancer (BC) Egyptian patients using multi-gene panel sequencing to better understand the contribution of the inherited germline mutations in BC predisposition. Moreover, to determine the actionable deleterious mutations associated with familial BC that might be used as biomarker for early cancer detection. Whole blood samples were collected from 101 Egyptian patients selected for BC family history, in addition to 50 age-matched healthy controls. A QIAseq targeted DNA panel (human BC panel) was used to assess the frequency of germline mutations. A total of 58 patients (57.4%) out of 101 were found to have 27 deleterious germline mutations in 11 cancer susceptibility genes. Of them, 32 (31.6%) patients carried more than one pathogenic mutation and each one carried at least one pathogenic mutation. The major genes harboring the pathogenic mutations were: ATM, BRCA2, BRCA1, VHL, MSH6, APC, CHEK2, MSH2, MEN1, PALB2, and MUTYH. Thirty-one patients (30.6%) had BRCA2 mutations and twenty (19.8%) had BRCA1 mutations. Our results showed that exon 10 and exon 11 harbored 3 and 5 mutations, respectively, in BRCA1 and BRCA2 genes. Our analysis also revealed that the VHL gene significantly co-occurred with each of the BRCA2 gene (p = 0.003, event ratio 11/21), the MSH2 gene (p = 0.01, 4/10), the CHEK2 gene (p = 0.02, 4/11), and the MSH6 gene (p = 0.04, 4/12). In addition, the APC gene significantly co-occurred with the MSH2 gene (p = 0.01, 3/7). Furthermore, there was a significant mutually exclusive event between the APC gene and the ATM gene (p = 0.04, 1/36). Interestingly, we identified population specific germline mutations in genes showing potentials for targeted therapy to meet the need for incorporating precision oncology into clinical practice. For example, the mutations identified in the ATM, APC, and MSH2 genes. Multi-gene panel sequencing was used to detect the deleterious mutations associated with familial BC, which in turns mitigate the essential need for implementing next generation sequencing technologies in precision oncology to identify cancer predisposing genes. Moreover, identifying DNA repair gene mutations, with focus on non-BRCA genes, might serve as candidates for targeted therapy and will be increasingly used in precision oncology.

Association between a polymorphic variant in the CDKN2B-AS1/ANRIL gene and pancreatic cancer risk.

Genes carrying high-penetrance germline mutations may also be associated with cancer susceptibility through common low-penetrance genetic variants. To increase the knowledge on genetic pancreatic ductal adenocarcinoma (PDAC) aetiology, the common genetic variability of PDAC familial genes was analysed in our study. We conducted a multiphase study analysing 7745 single nucleotide polymorphisms (SNPs) from 29 genes reported to harbour a high-penetrance PDAC-associated mutation in at least one published study. To assess the effect of the SNPs on PDAC risk, a total of 14 666 PDAC cases and 221 897 controls across five different studies were analysed. The T allele of the rs1412832 polymorphism, that is situated in the CDKN2B-AS1/ANRIL, showed a genome-wide significant association with increased risk of developing PDAC (OR=1.11, 95% CI=1.07-1.15, P=5.25 × 10-9 ). CDKN2B-AS1/ANRIL is a long noncoding RNA, situated in 9p21.3, and regulates many target genes, among which CDKN2A (p16) that frequently shows deleterious somatic and germline mutations and deregulation in PDAC. Our results strongly support the role of the genetic variability of the 9p21.3 region in PDAC aetiopathogenesis and highlight the importance of secondary analysis as a tool for discovering new risk loci in complex human diseases.