Germline Mutations In Susceptibility Genes Research Articles

SAT332 Genetic Characterization Of A Case of Pheochromocytoma In A Pulmonary Transplant Patient

Abstract Disclosure: F. Perreault: None. S. Parisien-Lasalle: None. J. Morisset: None. C. Poirier: None. C. Beauregard: None. R. Agnès: None. P. Ferraro: None. I. Bourdeau: None. Background: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) (PPGLs) are rare tumors arising from the chromaffin cells. Approximately 40% of PPGL patients carry germline mutations in susceptibility genes, including pseudohypoxic related SDHx and VHL genes. An association was described between hypoxemia and PPGLs, notably in higher altitude exposition and cyanotic congenital heart disease. In the latter, a chronic hypoxemic state can lead to gain of function somatic mutations in the EPAS1 gene that encodes for hypoxia-inducible factor 2-alpha (HIF-2) (1). Objective: To describe a rare case of PHEO in a pulmonary transplant patient and characterize the genetic background of the tumor. Clinical Case: A 66 year-old man underwent an unilateral lung transplant at the age of 47 for chronic obstructive pulmonary disease associated with alpha-1 antitrypsin deficiency. He required home oxygen therapy for 3 years prior to transplant and was known for new onset diabetes after transplant, chronic kidney disease, hypertension and paroxysmal atrial tachycardia. His family history was non-contributing. Nineteen years after transplant, a thoracic CT-scan showed a 6.1 cm x 3.9 cm right adrenal mass (HU of 7). Retrospectively, the mass had been present for the last seven years, and increased progressively in size. Diagnosis of PHEO was confirmed by the 24-h urinary catecholamines (norepinephrine 713 nmol/d (N< 650), epinephrine 588 nmol/d (N < 145), normetanephrines 900 nmol/d (N < 600) and metanephrines 1191 nmol/d (N < 370)). Chromogranin A was elevated (3297 ng/mL (N < 104)). The adrenal mass showed no uptake at 18F-FDG PET/CT imaging but fixation at MIBG scintigraphy. The patient received alpha blockers and underwent a laparoscopic right adrenalectomy. The pathology report confirmed a PHEO with a PASS score of 8 to 10. Eighteen months following the surgery, the patient showed no signs of biochemical or radiological recurrence. Genetic studies: 1) Germline PPGL multigene panel: After consent, the patient underwent a panel of 14 susceptibility genes for PPGLs (INVITAE, CA, USA) that revealed no pathogenic variants. 2) Somatic genetic analysis for EPAS1 gene: PHEO DNA was extracted and exons 9, 12 and 16 of the EPAS1 gene were studied by Sanger Sequencing. No pathogenic variants were identified.Conclusion: We report a rare case of PHEO in a pulmonary transplant patient. Our genetic analyses demonstrated the absence of a pathogenic germline variant in known susceptibility PPGL genes and no somatic mutations in the EPAS1 gene. Further work is needed to better understand the genetic and molecular events leading to PHEO in this specific case and determine its possible relationship with hypoxemia. (1) Vaidya A, Flores SK, Cheng Z-M, Nicolas M, Deng Y, Opotowsky AR, et al. EPAS1 Mutations and Paragangliomas in Cyanotic Congenital Heart Disease. New England Journal of Medicine. 2018;378(13):1259-61. Presentation: Saturday, June 17, 2023

Is Breast Conserving Surgery Efficacious in Breast Cancer Patients with BRCA1 or BRCA2 Germline Mutation?

The optimal surgical therapy for newly diagnosed breast cancer with germline mutations in susceptibility genes is still uncertain for many physicians. In this study, we aimed to determine the efficacy of breast conserving surgery (BCS) in breast cancer patients with BRCA1 or BRCA2 mutation by assessing its outcomes and locoregional recurrence (LR) rates. Seventy-five patients operated with BCS or mastectomy for breast cancer between 2006 and 2017 and had BRCA1 or BRCA2 mutation were included in the study. Effects of the performed breast surgery and clinicopathological characteristics on surgical outcomes, LR rates and survival were analyzed with showing the distribution of BRCA1 and BRCA2 germline mutations. The median age of the patients was 42 years (20-77). BRCA1 mutations were found in 46 (61.3%) patients and BRCA2 mutations in 29 (38.7%) patients. Compared to BRCA2 carriers, BRCA1 carriers were more likely to have higher tumor grade (84.8% vs 44.8%; p = 0.001) and non-luminal subtype tumors (67.4% vs 13.8%; p = 0.001). A total of 44 (58.7%) patients underwent unilateral mastectomy and 31 (41.3%) patients underwent BCS. At a median follow-up time of 60 (12-240) months, LR was observed in 6 patients equally divided in both BCS and mastectomy groups. LR rates were slightly higher after BCS versus mastectomy (9.7% and 6.8%, respectively). Additionally, there were no statistically significant differences in disease-free survival (DFS) and disease-specific survival (DSS) rates after 10 years in the BCS group versus the mastectomy group (p = 0.117 and 0.109, respectively), but in fact, the rates were better in the BCS group. Our findings indicate that BCS may serve as an efficacious alternative to mastectomy for breast cancer patients with BRCA1 or BRCA2 mutation. Additionally, tumor size, lymph node positivity, and TNM stage should be taken into consideration for a better surgical decision-making.

Increased Risk of Hereditary Prostate Cancer in Italian Families with Hereditary Breast and Ovarian Cancer Syndrome Harboring Mutations in BRCA and in Other Susceptibility Genes.

Hereditary prostate cancer (HPCa) has the highest heritability of any cancer in men. Interestingly, it occurs in several hereditary syndromes, including breast and ovarian cancer (HBOC) and Lynch syndrome (LS). Several gene mutations related to these syndromes have been identified as biomarkers in HPCa. The goal of this study was to screen for germline mutations in susceptibility genes by using a multigene panel, and to subsequently correlate the results with clinical and laboratory parameters. This was undertaken in 180 HBOC families, which included 217 males with prostate cancer (PCa). Mutational analysis was further extended to 104 family members of mutated patients. Screening of HBOC families revealed that 30.5% harbored germline mutations in susceptibility genes, with 21.6% harboring pathogenic variants (PVs) and 8.9% having variants of uncertain significance (VUS). We found PVs at similar frequency in BRCA1 and BRCA2 genes (8.8% and 9.4%, respectively), while 0.56% of PVs were present in well-established susceptibility genes PALB2, TP53 and RAD51C. Moreover, 0.56% of monoallelic PVs were present in MUTYH, a gene whose function in tumorigenesis in the context of PCa is still unclear. Finally, we reported double heterozygosity (DH) in BRCA1/2 genes in a single family, and found double mutation (DM) present in BRCA2 in a separate family. There was no significant difference between the mean age of onset of PCa in HBOC families with or without germline mutations in susceptibility genes, while the mean survival was highest in mutated patients compared to wild type. Furthermore, PCa is the second most recurrent cancer in our cohort, resulting in 18% of cases in both mutated and non-mutated families. Our investigation shows that PVs were located mostly in the 3′ of BRCA1 and BRCA2 genes, and in BRCA2, most PVs fell in exon 11, suggesting a mutation cluster region relating to risk of HPCa. A total of 65 family members inherited the proband’s mutation; of these, 24 developed cancer, with 41 remaining unaffected.

Personalized Management of Pheochromocytoma and Paraganglioma.

Pheochromocytomas/paragangliomas are characterized by a unique molecular landscape that allows their assignment to clusters based on underlying genetic alterations. With around 30% to 35% of Caucasian patients (a lower percentage in the Chinese population) showing germline mutations in susceptibility genes, pheochromocytomas/paragangliomas have the highest rate of heritability among all tumors. A further 35% to 40% of Caucasian patients (a higher percentage in the Chinese population) are affected by somatic driver mutations. Thus, around 70% of all patients with pheochromocytoma/paraganglioma can be assigned to 1 of 3 main molecular clusters with different phenotypes and clinical behavior. Krebs cycle/VHL/EPAS1-related cluster 1 tumors tend to a noradrenergic biochemical phenotype and require very close follow-up due to the risk of metastasis and recurrence. In contrast, kinase signaling–related cluster 2 tumors are characterized by an adrenergic phenotype and episodic symptoms, with generally a less aggressive course. The clinical correlates of patients with Wnt signaling–related cluster 3 tumors are currently poorly described, but aggressive behavior seems likely. In this review, we explore and explain why cluster-specific (personalized) management of pheochromocytoma/paraganglioma is essential to ascertain clinical behavior and prognosis, guide individual diagnostic procedures (biochemical interpretation, choice of the most sensitive imaging modalities), and provide personalized management and follow-up. Although cluster-specific therapy of inoperable/metastatic disease has not yet entered routine clinical practice, we suggest that informed personalized genetic-driven treatment should be implemented as a logical next step. This review amalgamates published guidelines and expert views within each cluster for a coherent individualized patient management plan.

Genetic Analysis and Clinical Characteristics of Hereditary Pheochromocytoma and Paraganglioma Syndrome in Korean Population.

BackgroundPheochromocytoma and paragangliomas (PPGL) are hereditary in approximately 30% to 40% cases. With the advancement of genetic analysis techniques, including next-generation sequencing (NGS), there were attempts to classify PPGL into molecular clusters. With NGS being applied to clinical settings recently, we aimed to review the results of genetic analysis, including NGS, and investigate the association with clinical characteristics in Korean PPGL patients.MethodsWe reviewed the medical records of PPGL patients who visited Severance hospital from 2006 to 2019. We documented the clinical phenotype of those who underwent targeted NGS or had known germline mutations of related genes.ResultsAmong 57 PPGL patients, we found 28 pathogenic germline mutations of susceptibility genes. Before the targeted NGS was implemented, only obvious syndromic feature lead to the Sanger sequencing for the specific genes. Therefore, for the exact prevalence, only patients after the year 2017, when targeted NGS was added, were included (n=43). The positive germline mutations were found in 14 patients; thus, the incidence rate is 32.6%. Patients with germline mutations had a higher likelihood of family history. There were significant differences in the type of PPGLs, percentage of family history, metastasis rate, presence of other tumors, and biochemical profile among three molecular clusters: pseudohypoxic tricarboxylic acid cycle-related, pseudohypoxic von Hippel-Lindau (VHL)/endothelial PAS domain-containing protein 1-related, and kinase-signaling group. Germline mutations were identified in seven PPGL-related genes (SDHB, RET, VHL, NF1, MAX, SDHA, and SDHD).ConclusionWe report the expected prevalence of germline mutations in Korean PPGL patients. NGS is a useful and accessible tool for genetic analysis in patients with PPGLs, and further research on molecular classification is needed for precise management.

Improving the overall diagnostic rate of early gastric cancer by managing family members with hereditary cancer syndromes.

The 5-year survival rate of early gastric cancer (EGC) is significantly higher compared with that of advanced gastric cancer; however, the general diagnostic rate of EGC remains low in certain regions. The discovery of novel methods for diagnosing EGC will be beneficial for the general population. Among all gastric cancers, ~90% are sporadic, 10% are characterized as familial aggregation, and 3–5% of gastric cancer is attributed to genetic predisposition. Compared with sporadic cancer types, hereditary cancer syndromes (HCS) are usually characterized by the development of cancer at an early age. The present study proposes an approach for promoting the diagnostic rate of EGC in the general population by managing individuals with a family history of HCS and germline mutations of susceptibility genes. The proposed management strategy has three steps: i) Establish family history archives of the general population to screen families with individuals who have HCS; ii) recommend genetic testing for the individuals among the selected families to screen for high-risk EGC, (i.e., with HCS family history and genetic mutations); and iii) perform active routine surveillance for selected individuals to improve the overall diagnostic rate of EGC in the general population. Individuals with a positive family history should undergo the process presented above early in life, while those with a negative history may undergo routine inspection when necessary. With advances in the medical field and reductions in the cost of genetic testing, the diagnostic rate of EGC may be improved.

Missed clinical clues in patients with pheochromocytoma/paraganglioma discovered by imaging.

BackgroundPheochromocytomas and paragangliomas (PPGLs) are rare but potentially harmful tumors that can vary in their clinical presentation. Tumors may be found due to signs and symptoms, as part of a hereditary syndrome or following an imaging procedure.ObjectiveTo investigate potential differences in clinical presentation between PPGLs discovered by imaging (iPPGLs), symptomatic cases (sPPGLs) and those diagnosed during follow-up because of earlier disease/known hereditary mutations (fPPGL).DesignProspective study protocol, which has enrolled patients from six European centers with confirmed PPGLs. Data were analyzed from 235 patients (37 iPPGLs, 36 sPPGLs, 27% fPPGLs) and compared for tumor volume, biochemical profile, mutation status, presence of metastases and self-reported symptoms. iPPGL patients were diagnosed at a significantly higher age than fPPGLs (P < 0.001), found to have larger tumors (P = 0.003) and higher metanephrine and normetanephrine levels at diagnosis (P = 0.021). Significantly lower than in sPPGL, there was a relevant number of self-reported symptoms in iPPGL (2.9 vs 4.3 symptoms, P < 0.001). In 16.2% of iPPGL, mutations in susceptibility genes were detected, although this proportion was lower than that in fPPGL (60.9%) and sPPGL (21.5%). Patients with PPGLs detected by imaging were older, have higher tumor volume and more excessive hormonal secretion in comparison to those found as part of a surveillance program. Presence of typical symptoms indicates that in a relevant proportion of those patients, the PPGL diagnosis had been delayed.PrécisPheochromocytoma/paraganglioma discovered by imaging are often symptomatic and carry a significant proportion of germline mutations in susceptibility genes.

Abstract 4274: The contribution of deleterious germ-line mutations of susceptibility genes to ovarian, fallopian tube, and peritoneal cancers in Japanese

Abstract Different ethnic groups present specific morphological features in ovarian cancer (OC). High-grade serous OC is more frequently found in Caucasian women, in contrast clear cell OC is more frequently found in East Asian women. Although inherited mutations of BRCA1 or BRCA2 (BRCA1/2) and other genes are known to predispose to OC, the contributions of these inherited mutations on disease burden is not well characterized in Japanese OC patients. Using a comprehensive genetic testing panel, the aim of our study was to identify the prevalence of pathogenic germ-line mutations of candidate genes associated with genetic predisposition to OC in Japanese patients with ovarian, fallopian tube, or peritoneal cancer.Samples from 236 individuals with unselected ovarian, fallopian tube, or peritoneal cancer, which were obtained from the Keio Women’s Health Biobank (KWB) from the School of Medicine at Keio University (Tokyo, Japan), were used for this study. Germ-line DNA was enriched using the SureSelect XT Target Enrichment System (Agilent Technologies) designed for 75 or 79 genes as a custom OC panel, followed by sequencing using MiSeq (Illumina). Detected variants, including point mutations, small indels, and a gross deletion, were classified according to the American College of Medical Genetics and Genomics (ACMG) recommendations. Furthermore, BRCA1/2 variants were interpreted using resources from Myriad Genetic Laboratories.Forty-two (17.8%) OC patients had germ-line mutations of cancer predisposition genes. BRCA1/2 pathological germ-line mutations were found in 27 cases (11.4%) while six cases (2.5%) had a mutation in a mismatch repair gene (MLH1, MSH2, MSH6, or PMS2). Furthermore, ten cases (4.2%) had germ-line mutations in the RAD51D, ATM, MRE11A, FANCC, or GABRA2 genes. Of patients with a BRCA1/2 mutation (n=27), we found that the most common histological subtype was high-grade serous OC, but we also found two cases with clear cell carcinoma. Of 42 cases with an inherited mutation, we found that 25% (6/24) had no family history of cancer, and 78% (31/41) were under 60 years old at diagnosis.We found that approximately 18% of unselected Japanese patients with ovarian, fallopian tube, or peritoneal cancer were associated with inherited mutations of cancer-predisposing genes. Our study demonstrates that comprehensive genetic testing is informative for all women with ovarian, fallopian tube, and peritoneal cancers to establish personalized clinical management and genetic counseling, irrespective of the patient's histological subtypes, ages or family histories. Citation Format: Akira Hirasawa, Issei Imoto, Takuya Naruto, Tomoko Akahane, Wataru Yamagami, Nobuyuki Susumu, Hitoshi Tsuda, Daisuke Aoki. The contribution of deleterious germ-line mutations of susceptibility genes to ovarian, fallopian tube, and peritoneal cancers in Japanese [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4274. doi:10.1158/1538-7445.AM2017-4274

Paragangliomas: Update on differential diagnostic considerations, composite tumors, and recent genetic developments

Recent developments in molecular genetics have expanded the spectrum of disorders associated with pheochromocytomas (PCCs) and extra-adrenal paragangliomas (PGLs) and have increased the roles of pathologists in helping to guide patient care. At least 30% of these tumors are now known to be hereditary, and germline mutations of at least 10 genes are known to cause the tumors to develop. Genotype-phenotype correlations have been identified, including differences in tumor distribution, catecholamine production, and risk of metastasis, and types of tumors not previously associated with PCC/PGL are now considered in the spectrum of hereditary disease. Important new findings are that mutations of succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD, and SDHAF2 (collectively "SDHx") are responsible for a large percentage of hereditary PCC/PGL and that SDHB mutations are strongly correlated with extra-adrenal tumor location, metastasis, and poor prognosis. Further, gastrointestinal stromal tumors and renal tumors are now associated with SDHx mutations. A PCC or PGL caused by any of the hereditary susceptibility genes can present as a solitary, apparently sporadic, tumor, and substantial numbers of patients presenting with apparently sporadic tumors harbor occult germline mutations of susceptibility genes. Current roles of pathologists are differential diagnosis of primary tumors and metastases, identification of clues to occult hereditary disease, and triaging of patients for optimal genetic testing by immunohistochemical staining of tumor tissue for the loss of SDHB and SDHA protein. Diagnostic pitfalls are posed by morphological variants of PCC/PGL, unusual anatomic sites of occurrence, and coexisting neuroendocrine tumors of other types in some hereditary syndromes. These pitfalls can be avoided by judicious use of appropriate immunohistochemical stains. Aside from loss of staining for SDHB, criteria for predicting risk of metastasis are still controversial, and "malignancy" is diagnosed only after metastases have occurred. All PCCs/PGLs are considered to pose some risk of metastasis, and long-term follow-up is advised.