Expression of Contactin 4 Is Associated With Malignant Behavior in Pheochromocytomas and Paragangliomas.

Context: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine, usually benign, tumors. Currently, the only reliable criterion of malignancy is the presence of metastases. Objective: The aim of this study was to identify genes associated with malignancy in PPGLs. Design: Transcriptomic profiling was performed on 40 benign and 11 malignant PPGLs. Genes showing a significantly different expression between benign and malignant PPGLs with a ratio ≥4 were confirmed and tested in an independent series by quantitative real-time polymerase chain reaction (qRT-PCR). Immunohistochemistry was performed for the validated genes on 109 benign and 32 malignant PPGLs. Functional assays were performed with hPheo1 cells. Setting: This study was conducted at the Department of Pathology of the Erasmus MC University Medical Center Rotterdam Human Molecular Genetics laboratory of the de Duve Institute, University of Louvain. Patients: PPGL samples from 179 patients, diagnosed between 1972 and 2015, were included. Main outcome measures: Associations between gene expression and malignancy were tested using supervised clustering approaches. Results: Ten differentially expressed genes were selected based on messenger RNA (mRNA) expression array data. Contactin 4 (CNTN4) was overexpressed in malignant vs benign tumors [4.62-fold; false discovery rate (FDR), 0.001]. Overexpression at the mRNA level was confirmed using qRT-PCR (2.90-fold, P = 0.02; validation set: 4.26-fold, P = 0.005). Consistent findings were obtained in The Cancer Genome Atlas cohort (2.7-fold; FDR, 0.02). CNTN4 protein was more frequently expressed in malignant than in benign PPGLs by immunohistochemistry (58% vs 17%; P = 0.002). Survival after 7 days of culture under starvation conditions was significantly enhanced in hPheo1 cells transfected with CNTN4 complementary DNA. Conclusion: CNTN4 expression is consistently associated with malignant behavior in PPGLs.

Sarcomatoid adrenocortical carcinoma: a comprehensive pathological, immunohistochemical, and targeted next-generation sequencing analysis.

Adrenocortical carcinomas (ACCs) with sarcomatous areas represent an extremely rare type of highly aggressive malignancy of unknown molecular pathogenesis. The current study was planned to gain insight into its molecular genetics using a targeted next-generation sequencing approach and to explore the status of epithelial-mesenchymal transition (EMT)-associated markers (E-/P-/N-cadherins, MMP-2/-9 and caveolin-1), downstream transcriptional regulators of EMT-related signaling pathways (ZEB-1/-2, Slug), stem cell factors (Oct3/4, LIN28, SOX2, SO17, NANOG, CD133, nestin), and markers of adrenocortical origin/tumorigenesis (SF-1, ß-catenin, p53) in phenotypically diverse tumor components of 6 cases. Thirteen pathogenic variants of ACC-associated TP53 and CTNNB1 genes were detected in epithelial and/or nonepithelial components in 4 out of 6 tumors. Three cases had identical mutations in distinct components, 1 of which contained TP53/CTNNB1 in 3 out of 5 components, whereas 1 harbored a single TP53 mutation only in the nonepithelial component. By immunohistochemistry, SF-1 and E-/P-/N-cadherins were found positive only in the epithelial component of all cases, whereas the nonepithelial components were mainly enriched for nestin, ZEB-1, and MMP-2/-9. ß-Catenin demonstrated an aberrant nuclear localization in the sarcomatoid component of 5 cases, whereas p53 was strongly positive in nonepithelial constituent in 4 of 6 cases. In summary, we have shown that Wnt/ß-catenin signaling pathway dysregulation and mutational inactivation of TP53 are common genetic events in sarcomatoid ACCs, a subset of which being monoclonal in origin. These tumors are enriched for EMT-related markers and stem cell factors, potentially conferring a poor prognosis, which might be exploited as novel therapeutic targets.

Complex MAX Rearrangement in a Family With Malignant Pheochromocytoma, Renal Oncocytoma, and Erythrocytosis.

CONTEXT: Familial pheochromocytoma (PCC) has been associated with germline mutations in 16 genes. Here we investigated three siblings presenting with bilateral pheochromocytomas. In addition, the index patient also exhibited renal oncocytoma and erythrocytosis, whereas the second sibling presented with a lymph node metastasis. DESIGN: First, single-nucleotide polymorphism array and exome sequencing were performed on germline and PCC-derived DNA to identify genomic alterations in the index patient. Second, alterations were confirmed and validated by Sanger sequencing, analyzed by (multiplexed) PCR to determine the loss of the wild-type allele, and investigated by immunohistochemistry in the tumors of the three siblings. RESULTS: The index patient's germline DNA revealed a large complex genomic alteration encompassing the intragenic and promoter regions of Myc-associated factor X (MAX) and alpha-(1,6)-fucosyltransferase (FUT8). In all three siblings the MAX alteration was confirmed, and the loss of the wild-type MAX and FUT8 alleles was demonstrated in all tumors. Uniparental disomy of chromosome 14q, previously demonstrated as a hallmark for MAX-related PCC, was shown in the index patient's PCC by single-nucleotide polymorphism array. Loss of MAX and FUT8 protein expression was demonstrated by immunohistochemistry in the tumors from the three siblings. CONCLUSIONS: Our results indicate that large genomic deletions of MAX should be considered in familial and bilateral PCC with prior negative testing for gene mutations. In addition, our results confirm that MAX is a tumor suppressor gene for renal oncocytomas.

Telomerase reverse transcriptase promoter mutations in tumors originating from the adrenal gland and extra-adrenal paraganglia.

Hotspot mutations in the promoter of the telomerase reverse transcriptase (TERT) gene have been recently reported in human cancers and proposed as a novel mechanism of telomerase activation. To explore TERT promoter mutations in tumors originating from the adrenal gland and extra-adrenal paraganglia, a set of 253 tumors (38 adrenocortical carcinomas (ACCs), 127 pheochromocytomas (PCCs), 18 extra-adrenal paragangliomas (ea PGLs), 37 head and neck PGLs (HN PGLs), and 33 peripheral neuroblastic tumors) was selected along with 16 human neuroblastoma (NBL) and two ACC cell lines to assess TERT promoter mutations by the Sanger sequencing method. All mutations detected were confirmed by a SNaPshot assay. Additionally, 36 gastrointestinal stromal tumors (GISTs) were added to explore an association between TERT promoter mutations and SDH deficiency. TERT promoter mutations were found in seven out of 289 tumors and in three out of 18 human cell lines; four C228T mutations in 38 ACCs (10.5%), two C228T mutations in 18 ea PGLs (11.1%), one C250T mutation in 36 GISTs (2.8%), and three C228T mutations in 16 human NBL cell lines (18.75%). No mutation was detected in PCCs, HN PGLs, neuroblastic tumors as well as ACC cell lines. TERT promoter mutations preferentially occurred in a SDH-deficient setting (P=0.01) being present in three out of 47 (6.4%) SDH-deficient tumors vs zero out of 171 (0%) SDH-intact tumors. We conclude that TERT promoter mutations occur in ACCs and ea PGLs. In addition, preliminary evidence indicates a potential association with the acquisition of TERT promoter mutations in SDH-deficient tumors.

Non-pheochromocytoma (PCC)/paraganglioma (PGL) tumors in patients with succinate dehydrogenase-related PCC-PGL syndromes: a clinicopathological and molecular analysis.

OBJECTIVE: Although the succinate dehydrogenase (SDH)-related tumor spectrum has been recently expanded, there are only rare reports of non-pheochromocytoma/paraganglioma tumors in SDHx-mutated patients. Therefore, questions still remain unresolved concerning the aforementioned tumors with regard to their pathogenesis, clinicopathological phenotype, and even causal relatedness to SDHx mutations. Absence of SDHB expression in tumors derived from tissues susceptible to SDH deficiency is not fully elucidated. DESIGN AND METHODS: Three unrelated SDHD patients, two with pituitary adenoma (PA) and one with papillary thyroid carcinoma (PTC), and three SDHB patients affected by renal cell carcinomas (RCCs) were identified from four European centers. SDHA/SDHB immunohistochemistry (IHC), SDHx mutation analysis, and loss of heterozygosity analysis of the involved SDHx gene were performed on all tumors. A cohort of 348 tumors of unknown SDHx mutational status, including renal tumors, PTCs, PAs, neuroblastic tumors, seminomas, and adenomatoid tumors, was investigated by SDHB IHC. RESULTS: Of the six index patients, all RCCs and one PA displayed SDHB immunonegativity in contrast to the other PA and PTC. All immunonegative tumors demonstrated loss of the WT allele, indicating bi-allelic inactivation of the germline mutated gene. Of 348 tumors, one clear cell RCC exhibited partial loss of SDHB expression. CONCLUSIONS: These findings strengthen the etiological association of SDHx genes with pituitary neoplasia and provide evidence against a link between PTC and SDHx mutations. Somatic deletions seem to constitute the second hit in SDHB-related renal neoplasia, while SDHx alterations do not appear to be primary drivers in sporadic tumorigenesis from tissues affected by SDH deficiency.

Akt/PKB-mediated phosphorylation of Twist1 promotes tumor metastasis via mediating cross-talk between PI3K/Akt and TGF-ß signaling axes.

UNLABELLED: Metastatic breast tumor cells display an epithelial-mesenchymal transition (EMT) that increases cell motility, invasion, and dissemination. Although the transcription factor Twist1 has been shown to contribute to EMT and cancer metastasis, the signaling pathways regulating Twist1 activity are poorly understood. Here, we show that Twist1 is ubiquitously phosphorylated in 90% of 1,532 invasive human breast tumors. Akt/protein kinase B (PKB)-mediated Twist1 phosphorylation promotes EMT and breast cancer metastasis by modulating its transcriptional target TGF-ß2, leading to enhanced TGF-ß receptor signaling, which in turn maintains hyperactive phosphoinositide 3-kinase (PI3K)/Akt signaling. Preventing phosphorylation of Twist1, as well as depletion of TGF-ß2, significantly impaired the metastatic potential of cancer cells in vivo, indicating a key role of phosphorylated Twist1 (phospho-Twist1) in mediating cross-talk between the PI3K/Akt and TGF-ß/Smad signaling axes that supports metastatic tumor development. Our results describe a novel signaling event linking PI3K/Akt hyperactivation in tumor cells to direct regulation of Twist1 activation and tumor metastasis. SIGNIFICANCE: We identified the first phospho-Twist1 transcriptional target TGF-ß2, which mediates cross-talk between PI3K/Akt and TGF-ß signaling and promotes tumor metastasis. Our results thus illustrate a direct role of PI3K/Akt signaling in metastatic cancer development and suggest that Twist1 phosphorylation could be a potential therapeutic target in clinical cancer treatment.

Loss of PKBß/Akt2 predisposes mice to ovarian cyst formation and increases the severity of polycystic ovary formation in vivo.

Ovarian cysts affect women of all ages and decrease fertility. In particular, polycystic ovarian syndrome (PCOS), in which multiple follicular cysts develop, affects 5-10% of women of reproductive age and can result in infertility. Current non-invasive treatments for PCOS can resolve cysts and restore fertility, but unresponsive patients must undergo severe ovarian wedge resection and resort to in vitro fertilization. PCOS is related to the deregulation of leutinizing hormone (LH) signaling at various levels of the hypothalamic-pituitary-ovarian axis and resultant hyperproduction of androgens. Because insulin resistance and compensatory hyperinsulinemia are observed in 50-70% of individuals with PCOS, deregulated insulin signaling in the ovary is considered an important factor in the disease. Here we report that aged mice specifically lacking the PKBß (also known as Akt2) isoform that is crucial for insulin signaling develop increased testosterone levels and ovarian cysts, both of which are also observed in insulin-resistant PCOS patients. Young PKBß knockout mice were used to model PCOS by treatment with LH and exhibited a cyst area that was threefold greater than in controls, but without hyperinsulinemia. Thus, loss of PKBß might predispose mice to ovarian cysts independently of hyperactive insulin signaling. Targeted therapeutic augmentation of specific PKBß signaling could therefore provide a new avenue for the treatment and management of ovarian cysts.

From man to mouse and back again: advances in defining tumor AKTivities in vivo.

AKT hyperactivation is a common event in human cancers, and inhibition of oncogenic AKT activation is a major goal of drug discovery programs. Mouse tumor models that replicate AKT activation typical of human cancers provide a powerful means by which to investigate mechanisms of oncogenic signaling, identify potential therapeutic targets and determine treatment regimes with maximal therapeutic efficacy. This Perspective highlights recent advances using in vivo studies that reveal how AKT signaling supports tumor formation, cooperates with other mutations to promote tumor progression and facilitates tumor-cell dissemination, focusing on well-characterized prostate carcinoma mouse models that are highly sensitive to AKT activation. The implications of these findings on the therapeutic targeting of AKT and potential new drug targets are also explored.