Whole Exome Sequencing Identifies Novel Genetic Alterations in Patients with Pheochromocytoma/Paraganglioma

Patient Sex and Origin Influence Distribution of Driver Genes and Clinical Presentation of Paraganglioma

Context

Sexual and ancestral differences in driver gene prevalence have been described in many cancers but have not yet been investigated in pheochromocytoma and paraganglioma (PPGL).

Objective

This study aims to assess whether sex and ancestry influence prevalence of PPGL driver genes and clinical presentation.

Methods

We conducted a retrospective analysis of patients with PPGL considering studies from 2010 onwards that included minimal data of type of disease, sex, mutated gene, and country of origin. Additional features were recorded when available (age, tumor location, bilateral or multifocal, somatic or germline, and metastatic disease).

Results

We included 2162 patients: 877 in Europe and 757 in Asia. Males presented more often with germline pathogenic variants (PVs) in genes activating hypoxia pathways (P = .0006) and had more often sympathetic paragangliomas (P = .0005) and metastasis (P = .0039). On the other hand, females with PPGLs due to MAX PVs were diagnosed later than males (P = .0378) and more often developed metastasis (P = .0497). European but not Asian females presented more often with PPGLs due to PVs in genes related to kinase signaling (P = .0052), particularly RET and TMEM127. Contrary to experiences from Europe, Asian patients with PPGL due to PVs in kinase signaling genes NF1, HRAS, and FGFR1 showed a high proportion of sympathetic tumors, while European patients almost exclusively had adrenal tumors (P < .005).

Conclusion

Personalized management of patients with PPGL might benefit from considering sexual and ancestral differences. Further studies with better clinically aligned cohorts from various origins are required to better dissect ancestral influences on PPGL development.

Case Report: Aggressive neural crest tumors in a child with familial von Hippel Lindau syndrome associated with a germline VHL mutation (c.414A>G) and a novel KIF1B gene mutation

Introduction

Von Hippel Lindau (VHL) syndrome is caused by an autosomal dominant hereditary or sporadic germline mutation of the VHL gene with more than five hundred pathogenic mutations identified. Pheochromocytomas and rarely paragangliomas occur in 10-50% of patients with VHL syndrome usually around 30 years of age and exceptionally before the age of 10.

Case presentation

We diagnosed a 9-year-old girl of normal appearance and severe refractory hypertension, with a norepinephrine-secreting pheochromocytoma related to VHL syndrome due to a known familial germline heterozygous mutation of VHL gene (c.414A>G), also present in three members of her family. At age 13, a pelvic tumor and a left adrenal pheochromocytoma that showed to be multi-metastatic to both lungs were discovered in the patient leading to left adrenalectomy and pelvic tumor resection. In addition to the germline VHL gene mutation, blood analysis using Next Generation Sequencing identified a novel heterozygous germline mutation of the KIF1B gene (c.3331_3332del; p.Asn1111Glnfs*21), which is only present in the girl and not the other family members. The patient is currently under steroid substitution therapy and leads a normal life.

Discussion

This family is notable by the early age of onset of multiple neural crest tumors associated with a high propensity for malignancy and metastatic spread. Most reports in the literature associated the VHL mutation with a later onset in adulthood and a benign course, which contrast with our findings and question the role of this mutation in the phenotype expressed in this kindred. Also, the presence of concomitant mutations in two susceptibility genes for neural crest tumors poses the question of their respective roles in the development of tumors in this family. Our familial case description illustrates the potential for systematic use of targeted Next Generation Sequencing with multi-gene panels in patients with neural crest tumors to confirm the role of known susceptibility genes as well as identifying new ones, but also to contribute to comprehensive databases on gene variants and their phenotypic counterparts in this specific area of medicine.

Systematic analysis of expression profiles and prognostic significance for MMDS-related iron-sulfur proteins in renal clear cell carcinoma

Mitochondrial metabolism disorders play an important role in the occurrence and development of tumors, and iron-sulfur protein is an important molecule for maintaining the normal function of mitochondria. However, the relationship between the expression, prognostic value, and immune infiltration of MMDS-related iron-sulfur protein genes in kidney renal clear cell carcinoma (KIRC) remains unclear. Based on online databases bioinformatics analysis was performed to evaluate the expression differences, survival impacts, immune infiltration, and prognostic significance of multiple mitochondrial dysfunction syndrome (MMDS)-related iron-sulfur protein genes in KIRC patients. For example, the protein-protein interaction (PPI) network was constructed using STRING and GEPIA database; Survival impacts were constructed by TCGA database; Immune infiltration was analyzed using TIMER database. There were significant differences in the mRNA expression levels of ISCA1, ISCA2, C1ORF69 and NFU1 in KIRC among different tumor grades and individual cancer stages. Furthermore, KIRC with high transcription levels of ISCA1, ISCA2, C1ORF69 and NFU1 (p < 0.01) was significantly associated with long overall survival (OS) and disease-free survival (DFS). In addition, overexpression of four genes, NFU1, ISCA1, ISCA2, and C1ORF69 in KIRC indicated a better prognosis. Further studies showed that immune cells had a significantly positive correlation with iron-sulfur protein family genes, including CD8+ T cells, CD4+ T cells and B cells. More importantly, the results of immunohistochemistry showed that the expression of NFU1, ISCA1, ISCA2 and C1ORF69 in normal tissues was higher than that in renal clear cell carcinoma tissues. In this study, we systematically analyzed the expression and prognostic value of iron-sulfur protein family genes in KIRC. More importantly, NFU1, ISCA1, ISCA2, and C1ORF69 are expected to become potential therapeutic targets for KIRC, as well as potential prognostic markers for improving the survival rate and prognostic accuracy of KIRC.

Mutations of 1p genes do not consistently abrogate tumor suppressor functions in 1p-intact neuroblastoma

Background

Deletion of 1p is associated with poor prognosis in neuroblastoma, however selected 1p-intact patients still experience poor outcomes. Since mutations of 1p genes may mimic the deleterious effects of chromosomal loss, we studied the incidence, spectrum and effects of mutational variants in 1p-intact neuroblastoma.

Methods

We characterized the 1p status of 325 neuroblastoma patients, and correlated the mutational status of 1p tumor suppressors and neuroblastoma candidate genes with survival outcomes among 100 1p-intact cases, then performed functional validation of selected novel variants of 1p36 genes identified from our patient cohort.

Results

Among patients with adverse disease characteristics, those who additionally had 1p deletion had significantly worse overall survival. Among 100 tumor-normal pairs sequenced, somatic mutations of 1p tumor suppressors KIF1Bβ and CHD5 were most frequent (2%) after ALK and ATRX (8%), and BARD1 (3%). Mutations of neuroblastoma candidate genes were associated with other synchronous mutations and concurrent 11q deletion (P = 0.045). In total, 24 of 38 variants identified were novel and predicted to be deleterious or pathogenic. Functional validation identified novel KIF1Bβ I1355M variant as a gain-of-function mutation with increased expression and tumor suppressive activity, correlating with indolent clinical behavior; another novel variant CHD5 E43Q was a loss-of-function mutation with decreased expression and increased long-term cell viability, corresponding with aggressive disease characteristics.

Conclusions

Our study showed that chromosome 1 gene mutations occurred frequently in 1p-intact neuroblastoma, but may not consistently abrogate the function of bonafide 1p tumor suppressors. These findings may augment the evolving model of compounding contributions of 1p gene aberrations toward tumor suppressor inactivation in neuroblastoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09800-0.

A case of juvenile-onset pheochromocytoma with KIF1B p.V1529M germline mutation

In 2008, a familial noradrenergic pheochromocytoma (PCC) with a KIF1B germline mutation in exon 41 was reported in a 24-year-old female proband and her family. However, in 2020, the same research group reported that the cause of PCC in this family was a MAX germline mutation and was not due to the KIF1B mutation. In this study, we investigated the pathogenicity of a KIF1B germline mutation detected in a 26-year-old woman with juvenile-onset noradrenergic PCC. She was surgically treated and did not have a family history of PCC. We performed whole-exome sequencing, Sanger sequencing, and immunohistochemical and gene expression analyses of catecholamine-synthesizing enzymes. Three tumors with associated somatic mutations were used as the control group. Whole-exome sequencing revealed a p.V1529M KIF1B germline mutation in exon 41 in our patient, and no other associated germline and somatic mutations, including MAX, were detected. Sanger sequencing confirmed the presence of both mutant and wild-type alleles in the tumor. Among the catecholamine-synthesizing enzymes, the expression of phenylethanolamine-N-methyl transferase was suppressed. An in silico analysis of the p.V1529M mutation showed a score suggestive of pathogenicity. After evaluation with the international guideline for sequence variants, p.V1529M mutation was still classified as a variant with uncertain significance; however, our data, including the in silico analysis data, provided certain evidences that met the criteria supporting its pathogenicity. Therefore, this study can support future studies in proving the pathogenicity of the KIF1B p.V1529M mutation.

A Case of Pheochromocytoma as a Subsequent Neoplasm in a Survivor of Childhood Embryonal Rhabdomyosarcoma

Childhood cancer survivors are at risk for subsequent neoplasms. We describe the clinical presentation and genetic testing of a 29-year-old woman diagnosed with a pheochromocytoma 22 years post-treatment for childhood embryonal rhabdomyosarcoma of the bladder. Genetic testing for cancer predisposition revealed a pathogenic variant in BRCA2 and a variant of uncertain significance in MSH2. Pathogenic variants associated with deafness were also identified in GJB2. This article reports a novel subsequent neoplasm following childhood embryonal rhabdomyosarcoma, and discusses the potential contribution of genetic cancer predisposition to this case as well as the clinical implications of genetic testing.

Diagnosis for Pheochromocytoma and Paraganglioma: A Joint Position Statement of the Korean Pheochromocytoma and Paraganglioma Task Force

Pheochromocytoma and paraganglioma (PPGLs) are rare catecholamine-secreting neuroendocrine tumors but can be life-threatening. Although most PPGLs are benign, approximately 10% have metastatic potential. Approximately 40% cases are reported as harboring germline mutations. Therefore, timely and accurate diagnosis of PPGLs is crucial. For more than 130 years, clinical, molecular, biochemical, radiological, and pathological investigations have been rapidly advanced in the field of PPGLs. However, performing diagnostic studies to localize lesions and detect metastatic potential can be still challenging and complicated. Furthermore, great progress on genetics has shifted the paradigm of genetic testing of PPGLs. The Korean PPGL task force team consisting of the Korean Endocrine Society, the Korean Surgical Society, the Korean Society of Nuclear Medicine, the Korean Society of Pathologists, and the Korean Society of Laboratory Medicine has developed this position statement focusing on the comprehensive and updated diagnosis for PPGLs.

Recurrent Germline Mutations of CHEK2 as a New Susceptibility Gene in Patients with Pheochromocytomas and Paragangliomas

PURPOSE

Recently, pheochromocytomas and paragangliomas (PPGLs) have been strongly suspected as hereditary tumors, as approximately 40% of patients carry germline mutations. In the cancers where defects occur to corrupt DNA repair and facilitate tumorigenesis, a CHEK2 strong association has been observed. Therefore, the purpose of this study was to investigate the effect of CHEK2 mutations for its possible pathogenicity in PPGLs.

METHODS

Four patients with CHEK2 mutations were recruited, as previously detected by the whole exome sequencing. Sanger sequencing was used to verify the germline mutations as well as the loss of heterozygosities (LOHs) in their somatic DNAs. Immunohistochemistry was used to analyze the expression of CHEK2 and its downstream target p53 Ser20 (phosphorylated p53).

RESULTS

The average age of studied patients was 44.25 ± 11.18 years, at the time diagnosis. One patient had multiple tumors which recurred quickly, while two patients had distant metastasis. None of the patient had any relevant family history. Four germline CHEK2 mutations were identified (c.246_260del; c.715G > A; c.1008+3A > T; and c.1111C > T). All the patients were predicted to have either pathogenic or suspected pathogenic mutations. There was no LOH of CHEK2 gene in somatic DNAs found. Additionally, neither CHEK2 proteins nor its downstream target p53 Ser20 were expressed in the tumor tissues. The inactivation of CHEK2 leads to the decrease in the p53 phosphorylation, which might promote tumorigenesis.

CONCLUSIONS

For the first time, CHEK2 was identified as a susceptibility gene for PPGLs. However, the penetrance of CHEK2 gene with genotype-phenotype correlation needs to be investigated.