EPAS1-related pheochromocytoma/paraganglioma.

In 2012, somatic EPAS1 pathogenic variants were found to cause a triad of pheochromocytoma/paragangliomas (PPGLs), polycythemia, and somatostatinoma. Since then, a limited number of studies on this subject have been reported, and data on the long-term outcome of metastatic disease are not available on this rare syndrome. We comprehensively reviewed EPAS1-related PPGL and describe an unusual patient who has been living with an EPAS1-related metastatic PPGL for 47 years. The results of this work show that EPAS1 pathogenic variants are rare, more in females and patients without pathogenic variants in other PPGL susceptibility genes. PPGLs are the most common manifestation followed by polycythemia and somatostatinoma. The EPAS1 pathogenic variants are often postzygotic, and the timing of their acquirement during embryonic development seems to correlate with the number and timing of development of the disease manifestations. Although recurrent and multifocal disease is common in EPAS1-related PPGL, distant metastases are uncommon and usually indolent. This is illustrated by a case of a man who was diagnosed at the age of 9 years and is currently 56 years old, alive, and well for 47 years with these metastases. He was found to have a somatic EPAS1 pathogenic variant (c.1592C>A, p.Pro531His) in bilateral pheochomocytoma and a pancreatic NET (somatostatinoma) but not in genomic DNA isolated from peripheral leukocytes. This and previous reports suggest that distant metastases are uncommon and less aggressive in EPAS1-related PPGLs compared to those found in other hereditary PPGLs.

LncRNA GAS8-AS1 dinucleotide genetic variantn.713A>G, n.714T>C is associated with early-stage disease, lymph node, and distant metastasis in differentiated thyroid cancer.

PURPOSE: Long noncoding RNAs (lncRNAs) play an essential role in the epigenetic regulation of various key genes involved in vital cellular functions. A somatic dinucleotide mutation in the lncRNA GAS8-AS1 was reported in Chinese papillary thyroid cancer. However, GAS8-AS1 dinucleotide alteration and its impact have never been explored in differentiated thyroid cancers and other populations. METHODS: We extracted genomic DNA from 265 DTCs and 97 normal healthy subjects, PCR amplified and Sanger sequenced to examine the GAS8-AS1 dinucleotide alteration. Calculated genotype/allele frequency to test Hardy-Weinberg Equilibrium (HWE) and performed a genetic model of inheritance to determine its association with DTC risk. Correlated the GAS8-AS1 dinucleotide variant distribution with clinical characteristics to find the association. Predicted GAS8-AS1 RNA secondary structure for wild type and variant using RemuRNA and RNAfold to assess the conformational changes. RESULTS: GAS8-AS1 dinucleotide alteration (n.713A > G, rs55742939; n.714T > C, rs61118444) identified in DTCs is a germline variant not somatic. The GAS8-AS1 genotype and allele frequency significantly deviated for HWE in DTCs (χ2 = 37.954; p = 0.0001) though not associated with its risk. Dinucleotide variant distribution was remarkably associated with early-stage disease (p = 0.002), lymph node (p = 0.01), and distant metastasis (p = 0.01) in DTCs. The GAS8-AS1 bearing dinucleotide variant markedly showed conformational change compared to that of its wild type. CONCLUSIONS: These findings indicate that GAS8-AS1 is genetically deregulated and implicated in several stages of DTC tumorigenesis suggesting it could be a promising prognostic biomarker in DTCs.

An aggressive cabergoline-resistant, temozolomide-responsive macroprolactinoma due to a germline SDHB pathogenic variant in the absence of paraganglioma or pheochromocytoma.

Context: Germline succinate dehydrogenase subunit B (SDHB) pathogenic variants are characteristic of familial paraganglioma (PGL) syndrome type 4. This syndrome frequently presents with abdominal PGL and has high tendency for locally aggressive behavior and distant metastasis. The vast majority of pituitary adenomas (PAs) are sporadic. However, PAs can be part of a number of familial tumor syndromes such as multiple endocrine neoplasia type 1 (MEN 1) or more rarely in association with pheochromocytoma and PGL (referred to as 3P syndrome). Only a limited number of PAs in association with SDHB-related PGL has been reported and the vast majority occurred subsequently or simultaneously with pheochromocytoma/PGL (collectively abbreviated as PPGL). In this report, we describe a young patient who had a giant pituitary macroprolactinoma resistant to large doses of cabergoline (CBG) and external beam radiotherapy (XRT). The patient did not have personal history of PPGL but was found to carry a germline SDHB pathogenic variant. Case report: A 38-year-old woman presented with headache, visual disturbances and galactorrhea and was found to have a 34-mm macroprolactinoma. She was treated with CBG 3-4 mg per week but PA continued to grow and caused significant cranial pressure symptoms. She underwent two transsphenoidal surgeries with rapid tumor recurrence after each one. She received XRT but PA continued to grow. She was finally treated with temozolomide with excellent response. Whole exome and subsequent Sanger sequencing confirmed that she has a pathogenic monoallelic SDHB mutation (NM_003000:c.C343T, p.R115*). PA tissue showed loss of heterozygosity for the same mutation and absent SDHB immunostaining confirming the pathogenic role of this SDHB mutation. Conclusion: Germline SDHB mutations can rarely cause PA in the absence of PPGL. They should be considered as a possible cause of aggressiveness and resistance to dopamine agonists in similar cases.

Thyroid Cancer, Neuroendocrine Tumor, Adrenal Adenoma, and Other Tumors in a Patient With a Germline PMS1 Mutation.

Context: Multiple tumors in the same patient suggest a genetic predisposition. Here, we report a patient who presented with several unusual types of malignant and benign tumors, presumably due to a pathogenic germline PMS1 mutation. Case: A 69-year-old woman presented with a 2-year history of abdominal pain and diarrhea. A computed tomography scan of the abdomen revealed a gastrointestinal neuroendocrine tumor (GiNET) with liver metastases and a nonfunctional benign adrenal adenoma. Bilateral large lung nodules were thought to be also metastases from the GiNET but turned out to be differentiated thyroid cancer metastases, which later progressed to anaplastic thyroid cancer (ATC) and led to the patient's demise. A right sphenoid wing meningioma causing partial hypopituitarism was diagnosed during her evaluation. A mammogram and a breast ultrasound revealed a 0.3-cm left breast nodule. Due to the multiplicity of her tumors, whole exome sequencing was performed. This revealed a previously described PMS1 deletion mutation causing a frameshift and truncation (NM_000534c.1258delC, p.His420Ilefs*22) but no other pathogenic variant in other cancer genes. DNA isolated from the ATC tumor tissue showed loss of heterozygosity of the same mutation, highly suggestive of its pathogenic role in thyroid cancer and presumably other tumors. Conclusion: This case reports several tumors including thyroid cancer, GiNET, adrenal adenoma, meningioma, and breast nodule, likely due to the PMS1 mutation found in this patient.

A molecular study of pediatric pilomyxoid and pilocytic astrocytomas: Genome-wide copy number screening, retrospective analysis of clinicopathological features and long-term clinical outcome.

Background: Pilocytic Astrocytoma (PA) is the most common pediatric brain tumors. PAs are slow-growing tumors with high survival rates. However, a distinct subgroup of tumors defined as pilomyxoid astrocytoma (PMA) presents unique histological characteristics and have more aggressive clinical course. The studies on genetics of PMA are scarce. Methods: In this study, we report one of the largest cohort of pediatric patients with pilomyxoid (PMA) and pilocytic astrocytomas (PA) in Saudi population providing a comprehensive clinical picture, retrospective analysis with long-term follow-up, genome-wide copy number changes, and clinical outcome of these pediatric tumors. We examined and compared genome-wide copy number aberrations (CNAs) and the clinical outcome of the patients with PA and PMA. Results: The median progression free survival for the whole cohort was 156 months and it was 111 months for the PMA, however, not statistically significantly different between the groups (log-rank test, P = 0.726). We have identified 41 CNAs (34 gains and 7 losses) in all tested patients. Our study yielded the previously reported KIAA1549-BRAF Fusion gene in over 88% of the tested patients (89% and 80% in PMA and PA, respectively). Besides the fusion gene, twelve patients had additional genomic CNAs. Furthermore, pathway and gene network analyses of genes in the fusion region revealed alterations in retinoic acid mediated apoptosis and MAPK signaling pathways and key hub genes that may potentially be involved in tumor growth and progression, including BRAF, LUC7L2, MKRN1, RICTOR, TP53, HIPK2, HNF4A, POU5F, and SOX4. Conclusion: Our study is the first report of a large cohort of patients with PMA and PA in the Saudi population that provides detailed clinical features, genomic copy number changes, and outcome of these pediatric tumors and may help better diagnosis and characterization of PMA.

Molecular Genetics of Diffuse Sclerosing Papillary Thyroid Cancer.

CONTEXT: Diffuse sclerosing papillary thyroid cancer (DSPTC) is rare, with limited data on its molecular genetics. OBJECTIVE: We studied the molecular genetics of a cohort of DSPTC. METHODS: DNA was isolated from paraffin blocks of 22 patients with DSPTC (15 females, 7 males, median age 18 years, range 8-81). We performed polymerase chain reaction-based Sanger sequencing and a next-generation sequencing (NGS) gene panel to characterize the genomic landscape of these tumors. We classified genetic alterations to definitely or probably pathogenic. Definitely pathogenic are genetic alterations that are well known to be associated with PTC (e.g., BRAFV600E). Probably pathogenic are other alterations in genes that were reported in The Cancer Genome Atlas or the poorly differentiated and anaplastic thyroid cancer datasets. RESULTS: Three tumors were tested only by Sanger sequencing and were negative for BRAFV600E, HRAS, KRAS, NRAS, TERT promoter, PTEN, and PIK3CA mutations. The other 19 tumors tested by NGS showed definitely pathogenic alterations in 10 patients (52.6%): 2/19 (10.5%) BRAFV600E, 5/19 (26.3%) CCDC6-RET (RET/PTC1), 1/19 (5.3%) NCOA4-RET (RET/PTC3), 1/19 (5.3%) STRN-ALK fusion, and 2/19 (10.6%) TP53 mutations. Probably pathogenic alterations occurred in 13/19 tumors (68.4%) and included variants in POLE (31.6%), CDKN2A (26%), NF1 (21%), BRCA2 (15.8%), SETD2 (5.3%), ATM (5.3%), FLT3 (5.3%), and ROS1 (5.3%). In 1 patient, the gene panel showed no alterations. No mutations were found in the RAS, PTEN, PIK3CA, or TERT promoter in all patients. There was no clear genotype/phenotype correlation. CONCLUSION: In DSPTC, fusion genes are common, BRAFV600E is rare, and other usual point mutations are absent. Pathogenic and likely pathogenic variants in POLE, NF1, CDKN2A, BRCA2, TP53, SETD2, ATM, FLT3, and ROS1 occur in about two-thirds of DTPTC.

The impact of thyroid imaging reporting and data system on the management of Bethesda III thyroid nodules.

Objectives: Atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS) is a heterogeneous category of fine needle aspiration cytology (FNAC); the management of this condition remains controversial. The clinical significance of such patients relies on the exclusion of malignancy. In this study, we aimed to determine the validity of the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) (2017) for predicting malignancy in this specific category of patients. Methods: In this study, we analysed a cohort of patients from our previous retrospective study. This four-year retrospective cohort study included all cases undergoing surgery with a cytological diagnosis of AUS/FLUS. We enrolled 110 cases with documented final histopathological diagnoses and ultrasound examinations. Results: The study included 83 females (75.5%) and 27 males (24.5%). The overall risk of malignancy (ROM) for AUS/FLUS thyroid nodules was 47.3%. The ROMs of TI-RADS 3 (TR3), TI-RADS 4 (TR4), and TI-RADS 5 (TR5) were 43.5%, 49.4% and 40%, respectively. There was no significant association between TI-RADS and final pathological analysis. Conclusions: Repeated FNAC with initial AUS/FLUS nodules is crucial. Our findings showed that ACR TI-RADS did not contribute to the cancer risk stratification of AUS/FLUS nodules. A large prospective multi-institutional study is now required to determine the validity of ACR TI-RADS and whether other adjunct clinical, cytological, molecular, or biochemical tools could facilitate the management of patients with these heterogeneous nodules.

Clinicopathologic and genomic characterizations of brain metastases using a comprehensive genomic panel.

Central nervous system (CNS) metastasis is the most common brain tumor type in adults. Compared to their primary tumors, these metastases undergo a variety of genetic changes to be able to survive and thrive in the complex tissue microenvironment of the brain. In clinical settings, the majority of traditional chemotherapies have shown limited efficacy against CNS metastases. However, the discovery of potential driver mutations, and the development of drugs specifically targeting affected signaling pathways, could change the treatment landscape of CNS metastasis. Genetic studies of brain tumors have so far focused mainly on common cancers in western populations. In this study, we performed Next Generation Sequencing (NGS) on 50 pairs of primary tumors, including but not limited to colorectal, breast, renal and thyroid tumors, along with their brain metastatic tumor tissue counterparts, from three different local tertiary centers in Saudi Arabia. We identified potentially clinically relevant mutations in brain metastases that were not detected in corresponding primary tumors, including mutations in the PI3K, CDK, and MAPK pathways. These data highlight the differences between primary cancers and brain metastases and the importance of acquiring and analyzing brain metastatic samples for further clinical management.

Case Report: Severe Gonadal Dysgenesis Causing 46,XY Disorder of Sex Development Due to a Novel NR5A1 Variant.

Mutations in the nuclear receptor subfamily 5 group A member 1 (NR5A1) are the underlying cause of 10-20% of 46,XY disorders of sex development (DSDs). We describe a young girl with 46,XY DSD due to a unique novel mutation of the NR5A1 gene. An 11-year-old subject, raised as a female, was noticed to have clitromegly. She looked otherwise normal. However, her evaluation revealed a 46,XY karyotype, moderate clitromegly but otherwise normal female external genitalia, undescended atrophied testes, rudimentary uterus, no ovaries, and lack of breast development. Serum testosterone and estradiol were low, and gonadotropins were elevated. Adrenocortical function was normal. DNA was isolated from the peripheral leucocytes and used for whole exome sequencing. The results were confirmed by Sanger sequencing. We identified a novel mutation in NR5A1 changing the second nucleotide of the translation initiation codon (ATG>ACG) and resulting in a change of the first amino acid, methionine to threonine (p.Met1The). This led to severe gonadal dysgenesis with deficiency of testosterone and anti-Müllerian hormone (AMH) secretion. Lack of the former led to the development of female external genitalia, and lack of the latter allowed the Müllerian duct to develop into the uterus and the upper vagina. The patient has a female gender identity. Bilateral orchidectomy was performed and showed severely atrophic testes. Estrogen/progesterone therapy was initiated with excellent breast development and normal cyclical menses. In summary, we describe a severely affected case of 46,XY DSD due to a novel NR5A1 mutation involving the initiation codon that fully explains the clinical phenotype in this subject.

Papillary Thyroid Cancer and a TERT Promotor Mutation-positive Paraganglioma in a Patient With a Germline SDHB Mutation.

Purpose: About 40% of paragangliomas (PGL) are due to germline mutations in one of several susceptibility genes. These genes rarely predispose to other non-PGL tumors. Here, we describe and functionally characterize a germline SDHB mutation in a patient who developed a BRAF V600E mutation-positive papillary thyroid cancer (PTC) and a TERT promotor mutation-positive PGL. Experimental design: A 28-year-old asymptomatic man was discovered incidentally to have a large left-sided mid-abdominal PGL and PTC. He underwent resection of the PGL and total thyroidectomy and neck dissection followed by I-131 adjuvant therapy for PTC. The histopathology revealed a high-grade PGL and a tall cell-variant PTC with lymph node metastases (T1b N1b M0). He soon developed PGL spinal metastases that have been rapidly progressing and is currently being treated with Lu177-dotatate therapy. Family screening revealed a positive SDHB mutation in the mother, a son, and a brother. Results: In addition to the heterozygous SDHB germline mutation (c.688C>T, p.Arg230Cys), molecular analysis revealed a somatic TERT promotor mutation (C228T) in PGL (negative in PTC) and a somatic BRAF V600E mutation in PTC (negative in PGL). Functional studies showed a higher proliferation rate in the mutant compared with the wild-type SDHB. Conclusion: Germline SDHB mutations rarely occur in patients with PTC and may contribute to its aggressiveness. Somatic TERT promotor mutations rarely occur in PGL and contribute to its aggressiveness and metastatic potential.

Fumarate Hydratase is a Novel Gene for Familial Non-Medullary Thyroid Cancer.

CONTEXT: The majority of cases of epithelial cell-derived thyroid cancer are sporadic. Familial non-medullary thyroid cancer (FNMTC) occurs in about 5% to 9% of cases, either as a part of known syndromes such as Cowden syndrome or in the form of familial clustering of 2 or more affected family members. Hereditary leiomyoma and renal cell cancer (HLRCC) syndrome is a rare familial cancer syndrome. The underlying etiology is heterozygous germline mutations of the fumarate hydratase (FH) gene. In addition to extensive uterine and skin leiomyomas and RCC, other tumors may arise in this syndrome. However, thyroid cancer has never been described as part of HLRCC. Here, we describe a woman who presented with an aggressive poorly differentiated thyroid cancer (PDTC) and was found to have HLRCC syndrome because of a novel heterozygous germline FH mutation. RESULTS: A 43-year-old woman presented with a large lower neck mass that was found to be PDTC. During her evaluation, she was found to have extensive uterine leiomyomatosis and bilateral adrenal nodules. Whole exome and subsequent Sanger sequencing of leucocyte DNA revealed a novel monoallelic nonsense FH mutation (c.760C>T, p.Q254*). Sequencing of the thyroid tumor tissue showed a biallelic loss at the same mutation site (loss of heterozygosity) and immunohistochemistry of the PDTC showed loss of FH staining in the tumor tissue, indicating the pathogenic role of this mutation in the development of PDTC in this patient. CONCLUSION: Thyroid cancer is a novel feature of the FH-related HLRCC syndrome. This syndrome can be added to the rare genetic causes of syndromic FNMTC.

Controversy on the management of patients carrying RET p.V804M mutation.

CONTEXT: RET p.V804M is classified as a moderate risk mutation for familial medullary thyroid cancer (FMTC). There is a significant controversy on the management of patients carrying this mutation. We describe a family incidentally discovered to have this mutation and review the literature on RET p.V804M mutation. RESULTS: The proband was born to first-degree relative parents. He was noticed to have hypertrophy of some parts of the body and vascular skin changes. Whole-exome sequencing of DNA extracted from a skin biopsy showed a mutation in the PIK3CA (c.3132T>G, p.ASN1044LYS). This variant was not found in DNA extracted from blood. This confirmed the diagnosis of CLOVES syndrome (Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi and Scoliosis, skeletal or spinal anomalies). Another incidentally found mutation in the skin biopsy and blood sample was RET p.V804M. Although there was no family history of MTC or MEN 2 syndromes, family screening revealed RET p.V804M mutation and FMTC in the proband's father, paternal grandmother, one sister, and one aunt. There was significant interfamilial heterogeneity in the age of presentation and pathology. A review of literature showed that RET p.V804M mutation is a moderate risk mutation associated with late-onset FMTC, usually at middle to old age. CONCLUSION: Despite the controversy and the heterogeneous presentation of patients with RET p.V804M mutation, our study and review of the literature suggest that this seemingly "low" risk mutation is associated with late-onset but potentially aggressive MTC. This indicates the need for follow-up and timely intervention based on calcitonin level elevation.

Analysis of ALK, IDH1, IDH2 and MMP8 somatic mutations in differentiated thyroid cancers.

Anaplastic lymphoma kinase (ALK), isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) and matrix metalloproteinase 8 (MMP8) gene mutations have been frequently reported in human cancers; however, to the best of our knowledge, they have not been specifically examined in differentiated thyroid cancers (DTCs). Therefore, the present study aimed to determine the somatic mutational frequencies of these genes in DTCs. Mutational analysis of the ALK (exons 23, 24 and 25), IDH1 (exon 4), IDH2 (exon 4), and MMP8 (all exons 1-10) was performed in 126, 271, 271 and 50 DTCs, respectively. All the indicated exons were PCR-amplified and the PCR products were directly sequenced by Sanger sequencing. The present study identified a high frequency (86%; 43/50) of MMP8 single nucleotide polymorphism (SNP) and also found some rare SNPs of this gene (S3C, T32I, L310P and K460T) in DTCs but no somatic mutation in ALK, IDH1, IDH2 and MMP8. Analyses of 414 DTCs from The Cancer Genome Atlas revealed rare ALK (1%) and MMP8 (0.24%) mutations and none in IDH1 and IDH2. Conversely, analyses of 117 aggressive thyroid cancers [84, poorly differentiated thyroid cancer (PDTC); 33, anaplastic thyroid cancer (ATC)] from the Memorial Sloan Kettering Cancer Center cohort revealed ALK mutations in 3% of ATCs and fusions in 3.6% of PDTCs. IDH1 mutation was identified in 1.25% of PDTCs but not in ATC. IDH2 mutation was identified in 3% of ATCs but not in PDTC. The present study demonstrated that these genes are less frequently mutated in DTCs, but common in ATCs and PDTCs. It suggests that these genes serve a role in a small portion of DTCs and a more important role in ATCs and PDTCs and may serve as potential therapeutic targets in these subsets.

Single nucleotide polymorphisms in matrix metalloproteinase 2 (MMP2) enhance BRAFV600E mutation-mediated oncogenicity and invasiveness of papillary thyroid cancer cells.

Thyroid cancer is a common endocrine neoplasm. Despite its good prognosis, it can lead to significant morbidity and mortality due to metastasis and recurrence. However, the factors involved in metastasis are not well studied. Therefore, we selected matrix metalloproteinases 2 (MMP2) and determined whether it has any role in thyroid cancer. We sequenced the exons of MMP2 in 211 samples including 16 multi-nodular goiters and 195 differentiated thyroid cancers. We identified four non-synonymous single nucleotide polymorphisms (SNPs) of the MMP2 gene in 3.06% (6/195) thyroid cancers. Of the four tumors harboring MMP2 SNPs, three (75%) concomitantly had BRAFV600E. Hence, we speculated that the MMP2 SNPs may cooperate with BRAFV600E in promoting tumor aggressiveness. Overexpression of two MMP2 SNPs (P38L and T458I) exhibited markedly enhanced gelatinase activity with an intact dimerization and induced strong cortactin foci formation in HEK293T cells. Stable expression of the two MMP2 SNPs in BRAFV600E positive BCPAP cells dramatically enhanced cell proliferation, colony formation, and focus formation. Analysis of the morphology of MMP2 SNP bearing BCPAPV600E cells exhibited highly invasive phenotypes characterized by a high rate of wound healing and enhanced cell invasion compared with parental BCPAPV600E cells bearing vector. We also determined that BCPAPV600E cells stably transfected with MMP2 SNPs were highly sensitive to the treatment of BRAF inhibitor, PLX4720. Our study demonstrates that MMP2 SNPs could cooperate with BRAFV600E to promote oncogenicity, migration, and invasiveness of PTC cells. These results suggest that a subset of papillary thyroid cancer with this genetic makeup may benefit from BRAF-mediated therapeutic interventions.

One genotype, many phenotypes: SDHB p.R90X mutation-associated paragangliomas.

CONTEXT: SDHB p.R90X germline mutation is the most common genetic alteration in our patients with familial or apparently sporadic pheochromocytoma/paraganglioma (PPGL). OBJECTIVE: To analyze the clinical and pathological characteristics, response to therapy, and outcome of patients with SDHB p.R90X-associated PPGL and describe the clinical phenotypic variability in the patients carrying this mutation. METHODS: We reviewed the clinical and pathological characteristics and analyzed the phenotypic variability of all 13 patients that have SDHB p.R90X mutation-associated PPGL. RESULTS: Thirteen patients (five females and eight males). The median age at diagnosis was 23 years (range 8-43). Although the mutation was the same, there was significant phenotypic variability between patients and even within the same family. Four patients (30.8%) had a family history of PPGL and six patients (46%) had distant metastasis. Surgery of the primary tumor was performed in 11 patients (84.6%). Two patients had inoperable PPGL. Patients with metastasis received different combinations of chemotherapy, Lu177 radiotherapy, multikinase inhibitors, and external irradiation. Only five patients (38.5%) were in remission at a follow-up duration of 4-9 years. The other patients either died due to their disease progression (four patients, 30.8%) or continue to have progressive disease (two patients, 15.4%) or recurrence (one patient, 7.7%). Patients with distant metastasis were older, had larger primary tumors, were more likely to have a family history of PPGL and had a worse outcome. CONCLUSION: SDHB p.R90X mutation-associated PPGL have significant phenotypic variability and are associated with a high risk of distant metastasis and mortality.

Genetic Alterations in Pediatric Thyroid Cancer Using a Comprehensive Childhood Cancer Gene Panel.

CONTEXT: Pediatric differentiated thyroid cancer (DTC) differs from adult DTC in its underlying genetics and clinicopathological features. In this report, we studied these aspects in 48 cases of pediatric DTC. PATIENTS AND METHODS: We used the comprehensive Oncomine Childhood Cancer Gene panel on Ion Torrent next-generation sequencing platform. We included 48 patients (37 girls and 11 boys) with pediatric DTC (median age 17 years; range, 5-18 years) and studied the association between these genetic alterations and the clinicopathological features and outcome. RESULTS: Of 48 tumors, 33 (69%) had somatic genetic alterations that were mutually exclusive except in one tumor. BRAFV600E and RET-PTC1 were the most common, occurring in 9 different tumors (19%) each. RET-PTC3 and ETV6-NTRK3 were the next most common, with each occurring in 4 different tumors (8%). Other genetic alterations including EML4-NTRK1, EML4-ALK, NRAS, KRAS, PTEN, and CREBBP occurred once each. There were no differences between those who had mutations and those without mutations with respect to age, sex, tumor multifocality, extrathyroidal extension, vascular invasion, lymph node or distant metastasis, and American Thyroid Association response to therapy status at the last follow-up visits. Similarly, none of these factors was different between those with fusion genes vs single-point mutations vs no mutations. CONCLUSIONS: In pediatric DTC, fusion genes are more common than single-point mutations. The most common genetic alterations are RET-PTC1, BRAFV600E, RET-PTC3, and ETV6-NTRK3. Other alterations occur rarely. Genetic alterations do not correlate with the clinicopathological features or the outcome.

Infantile atypical subependymal giant cell astrocytoma.

Subependymal giant cell astrocytoma is a benign WHO grade I intraventricular tumor arise in patients with tuberous sclerosis complex. Previous reported described histopathological predictors of more aggressive forms, terms atypical SEGA in infantile age group. Other reports showed possible transformation of SEGA into glioblastoma, or misdiagnosis as glioblastoma due to the presence of atypical histopathological features. Here, we report a case of an infant who presented with right frontal extraventricular SEGA and underwent craniotomy with complete resection. Eight months later, he presented with fast recurrence in same location with midline shift and subfalcine herniation. Histopathological description showed high grade features including Ki labeling index of 60%, atypical mitotic figures, cellular plemorphism and necrosis. We also discussed the possible presence of different entity (termed atypical SEGA) which may have more aggressive clinical course, with literature review of predictors of SEGA aggressiveness and possible transformation/misdiagnosis as glioblastoma.

Angiocentric glioma of brainstem.

Angiocentric glioma is a rare brain tumor commonly found in frontal or temporal lobes. It has a benign course, and surgical resection can be curative. Brainstem location is extremely rare, with only six cases reported so far in the literature. In the present study, the seventh case of brainstem angiocentric glioma has been reported, and its course in comparison with supratentorial location and the role of molecular diagnosis has been discussed.

Mutational profile and genotype/phenotype correlation of non-familial pheochromocytoma and paraganglioma.

About 30%-40% of patients with pheochromocytoma (PCC) and paraganglioma (PGL) have underlying germline mutations in certain susceptibility genes despite absent family history of these tumors. Here, we present mutational profile of 101 such patients with PCC/PGL (PPGL) from the highly consanguineous population of Saudi Arabia. Results: Of 101 cases with PPGL, 37/101 (36.6%) had germline mutations. Mutations were detected in 30 cases by PCR and direct Sanger sequencing and in 7 additional cases by NGS. The most commonly mutated gene was SDHB (21/101 cases, 20.8%) and the most common SDHB mutation was c.268C>T, p.R90X occurring in 12/21 (57%) cases. Mutations also occurred in SDHC (4/101, 3.96%), SDHD (3/101, 3%), VHL (2/101, 2%) and MAX (2/101, 2%) genes. The following genes were mutated in 1 patient each (1%), RET, SDHA, SDHAF2, TMEM127 and NF1. Metastatic PPGL occurred in 6/21 cases (28.6%) with SDHB mutations and in 1 case with SDHAF2 mutation. Patients and Methods: DNA was isolated from peripheral blood (53 patients) or from non-tumorous formalin fixed paraffin embedded (FFPE) tissue (48 patients). PCR and direct Sanger sequencing of RET, SDHx, VHL, MAX and TMEM127 genes were performed. Cases without mutations were subjected to whole exome sequencing using next generation sequencing (NGS). Conclusion: About 37% of PPGL without family history of such tumors harbor germline mutations. The most commonly mutated gene is SDHB followed by SDHC, SDHD, VHL, MAX and rarely RET, SDHA, SDHAF2, TMEM127 and NF1. SDHB mutations were associated with metastatic PPGL in more than a quarter of cases.

GPCR-mediated PI3K pathway mutations in pediatric and adult thyroid cancer.

Whole exome sequencing (WES) recently identified frequent mutations in the genes of GPCR-mediated PI3K pathway (LPAR4, PIK3CA, and PTEN) in a Chinese population with papillary thyroid cancers (PTCs). The study found LPAR4 mutations as novel gene mutations in adult population with differentiated thyroid cancer (DTC). Here, we determine the prevalence of somatic mutations in this pathway (LPAR4 (exon 1), PIK3CA (exons 9 and 20) and PTEN (exons 5, 6, 7 and 8) in 323 thyroid samples consisting of 17 multinodular goiters (MNG), 89 pediatric DTCs, 204 adult DTCs, and 13 aggressive thyroid cancers including 10 poorly differentiated (PDTC) and 3 anaplastic thyroid cancer (ATC) from another ethnic population. We found 3.37% and 2.45% (includes Q214H, a novel PTEN mutation) in GPCR-mediated PI3K pathway of pediatric and adult DTCs, respectively. Analyses of 507 DTCs from thyroid Cancer Genome Atlas data (TCGA) revealed a low prevalence of mutations in this pathway (1.18%). In 13 cases with PDTC and ATC, we found no mutation in genes of this pathway. By contrast, analyses of 117 aggressive thyroid cancers (PDTC and ATC) from TCGA showed 13% of mutations in this pathway. Moreover, analyses of 1080 pan-cancer cell lines and 9020 solid tumors of TCGA data revealed high rates of mutations in this pathway (cell lines, 24.8%; tumors, 24.8%). In addition, PIK3CA + PTEN (p = <0.001) and LPAR4 + PIK3CA (p = 0.003) significantly co-occurred. Our study reveals a low prevalence of GPCR-mediated PI3K pathway mutations both in pediatric and adult DTCs corroborating the TCGA data and suggests a significant role of this pathway only in a small portion of DTCs. The high prevalence of mutations in this pathway in other solid malignancies suggests an important role in their pathogenesis making it an attractive target for therapeutic intervention both in a small subset of DTCs and other solid cancers.