Overexpression of TEAD4 in atypical teratoid/rhabdoid tumor: New insight to the pathophysiology of an aggressive brain tumor

BackgroundAtypical teratoid/rhabdoid tumor (AT/RT) is a highly malignant embryonal brain tumor that occurs mainly in early childhood. Although most of the tumors are characterized by inactivating mutations of the tumor suppressor gene, SMARCB1, the biological basis of its tumorigenesis and aggressiveness is still unknown.ProcedureWe performed high‐throughput copy number variation analysis of primary cell lines generated from primary and relapsed tumors from one of our patients to identify new genes involved in AT/RT biology. The expression of the identified gene was validated in 29 AT/RT samples by gene expression profiling, quantitative real‐time polymerase chain reaction, and immunohistochemistry (IHC). Furthermore, we investigated the function of this gene by mutating it in rhabdoid tumor cells.ResultsTEAD4 amplification was detected in the primary cell lines and its overexpression was confirmed at mRNA and protein levels in an independent cohort of AT/RT samples. TEAD4’s co‐activator, YAP1, and the downstream targets, MYC and CCND1, were also found to be upregulated in AT/RT when compared to medulloblastoma. IHC showed TEAD4 and YAP1 overexpression in all samples. Cell proliferation and migration were significantly reduced in TEAD4‐mutated cells.ConclusionsWe report the overexpression of TEAD4 in AT/RT, which is a key component of Hippo pathway. Recent reports revealed that dysregulation of the Hippo pathway is implicated in tumorigenesis and poor prognosis of several human cancers. Our results suggest that TEAD4 plays a role in the pathophysiology of AT/RT, which represents a new insight into the biology of this aggressive tumor.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137309/1/pbc26398_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137309/2/pbc26398.pd

Childhood carcinoid tumors: description of a case series in a Brazilian cancer center

CONTEXT AND OBJECTIVE: Carcinoid tumors are very rare both in children and adults. About 85% of these tumors develop in the gastrointestinal tract. The objective of the present study was to describe our experience with children treated of carcinoid tumors, and investigate the frequency morphological findings and results. DESIGN AND SETTING: Report on case series, at the Department of Pediatrics of Centro de Tratamento e Pesquisa Hospital do Câncer, São Paulo. METHODS: This was a retrospective analysis of clinical pathological data and outcomes among children (< 18 years old) with carcinoid tumors admitted from January 1, 1990, to December 31, 2001. RESULTS: Nine patients (mean age 12.2 years) were included: six girls and three boys (2:1), all of them Caucasian. In eight cases (89%), the primary tumor site was the appendix and in one (11%) it was the left bronchus. For those with primary tumor in the appendix, the main complaint was abdominal pain, which led to appendectomy. Only one patient underwent right hemicolectomy due to tumor extension into the serosa. The patient with bronchial tumor underwent left pneumonectomy. All patients had localized disease and are alive and free of disease. They have had follow-ups lasting from 1 to 11 years (mean of 3.5 years). CONCLUSION: Although the majority of carcinoid tumors arise from the appendix, these tumors can also occur in other primary sites. Surgical resection at an early stage allows for good prognosis without the need for any adjuvant treatment

Pan-cytokeratin immunoexpression in Wilms' tumors: a simple approach for understanding tumor epithelial differentiation

Wilms' tumor is one of the most common solid tumors in children and is an interesting model for understanding the pathogenesis of embryonal tumors. Cytokeratins are intracellular fibrous proteins present in tissue of epithelial origin. The immunoexpression of the pan-cytokeratin AE1AE3 was studied in paraffin-embedded tissue sections from 24 Wilms' tumors (12 with nephrogenic rests) and also tissue samples from 15 corresponding normal kidneys, to evaluate epithelial differentiation in the genesis of Wilms' tumor. We observed that the intensity of the expression of AE1AE3 in the epithelial component of Wilms' tumors directly correlated with the degree of maturity of the epithelial structures correspondent to the collecting ducts

Polo-Like Kinase 4 (PLK4) Is Overexpressed in Central Nervous System Neuroblastoma (CNS-NB)

Neuroblastoma (NB) is the most common extracranial solid tumor in pediatrics, with rare occurrences of primary and metastatic tumors in the central nervous system (CNS). We previously reported the overexpression of the polo-like kinase 4 (PLK4) in embryonal brain tumors. PLK4 has also been found to be overexpressed in a variety of peripheral adult tumors and recently in peripheral NB. Here, we investigated PLK4 expression in NBs of the CNS (CNS-NB) and validated our findings by performing a multi-platform transcriptomic meta-analysis using publicly available data. We evaluated the PLK4 expression by quantitative real-time PCR (qRT-PCR) on the CNS-NB samples and compared the relative expression levels among other embryonal and non-embryonal brain tumors. The relative PLK4 expression levels of the NB samples were found to be significantly higher than the non-embryonal brain tumors (p-value &lt; 0.0001 in both our samples and in public databases). Here, we expand upon our previous work that detected PLK4 overexpression in pediatric embryonal tumors to include CNS-NB. As we previously reported, inhibiting PLK4 in embryonal tumors led to decreased tumor cell proliferation, survival, invasion and migration in vitro and tumor growth in vivo, and therefore PLK4 may be a potential new therapeutic approach to CNS-NB