Atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumor

A malignant WHO grade IV embryonal tumor of the CNS comprised of poorly differentiated elements and rhabdoid cells and, by definition, includes inactivation of SMARCB1 (INI1) or (extremely rarely) SMARCA4 (BRG1). Histologically similar tumors lacking these molecular genetics should be classified as CNS embryonal tumors with rhabdoid features.

Many of these tumors were probably previously misdiagnosed as MDBs. Occurs primarily in infants and children (> 90% are < 5 years of age, with most age < 2 years). A minority are associated with primary renal rhabdoid tumor. The ratio of supratentorial to infratentorial AT/RTs is 4:3. Posterior fossa AT/RTs may occur in the cerebellar hemispheres, cerebellopontine angle (CPA) and brainstem. 33% have CSF spread at presentation. Althogh the prognosis is poor, not all AT/RTs have the same behavior, and at least 2 different molecular classes have been identified.


Atypical teratoid rhabdoid tumor (AT/RT) is a rare, highly malignant, true rhabdoid tumor in the central nervous system predominantly presenting in young children.

It was originally described a histological variant of Wilm’s tumor in 1978.


Atypical teratoid rhabdoid tumors (ATRTs) comprise at least two transcriptional subtypes with different clinical outcomes; however, the mechanisms underlying therapeutic heterogeneity remained unclear. In a study, Torchia et al., analyzed 191 primary ATRTs and 10 ATRT cell lines to define the genomic and epigenomic landscape of ATRTs and identify subgroup-specific therapeutic targets.

They found ATRTs segregated into three epigenetic subgroups with distinct genomic profiles, SMARCB1 genotypes, and chromatin landscape that correlated with differential cellular responses to a panel of signaling and epigenetic inhibitors. Significantly, they discovered that differential methylation of a PDGFRB-associated enhancer confers specific sensitivity of group 2 ATRT cells to dasatinib and nilotinib, and suggest that these are promising therapies for this highly lethal ATRT subtype 1).

Classification

AT/RT can occur anywhere in the central nervous system (CNS) including the spinal cord. About 60% will be in the posterior cranial fossa (particularly the cerebellum). One review estimated 52% posterior fossa, 39% sPNET (supratentorial primitive neuroectodermal tumors), 5% pineal, 2% spinal, and 2% multi-focal.

In the United States, three children per 1,000,000 or around 30 new AT/RT cases are diagnosed each year. AT/RT represents around 3% of pediatric cancers of the CNS.

Around 17% of all pediatric cancers involve the CNS; it is the most common childhood solid tumor.

see Adult sellar atypical teratoid rhabdoid tumor.

see Cerebellopontine angle atypical teratoid rhabdoid tumor.

Atypical Teratoid Rhabdoid Tumor of the Cauda Equina.

Atypical Teratoid Rhabdoid Tumor of the Conus Medullaris.

Pathology

Typically shows rhabdoid cells which can also be seen in other tumors, but it is differentiated from other tumors by the specific genetic alteration involving the SMARCB1 gene. Only a few cases of AT/RT arising in low-grade glioma have been reported. A 13-year-old girl presented with headache, dizziness, nausea and vomiting.A 4.7 cm cerebellar mass was found on MRI.The mass was totally removed. Histologically, the tumor revealed two distinct morphologic appearances: central areas of AT/RT containing rhabdoid cells and sarcomatous component in the background of pleomorphic xanthoastrocytoma(PXA). Immunohistochemically, PXA areas retained nuclear expression of INI-1 and low Ki-67 proliferation index, whereas AT/RT component showed loss of INI-1 nuclear expression and markedly elevated Ki-67 proliferation index. Epithelial membrane antigen (EMA), smooth muscle actin (SMA), and p53 protein were positive only in AT/RT. BRAF V600E mutation was identified in PXA by real-time polymerase chain reaction.We report a rare case of AT/RT arising in PXA which is supposed to progress by inactivation of INI-1 in a pre-existing PXA 2).

Treatment

Atypical teratoid rhabdoid tumor treatment.

Outcome

Patient age at the time of diagnosis, supratentorial location of the mass and fewer complications with adjuvant treatments seem to be factors yielding good prognosis for AT/RT tumors. In agreement with the latest international protocols, multidisciplinary treatment is the ideal treatment, consisting of radiotherapy and chemotherapy after complete tumor resection 3).

Case series

Twenty-eight pediatric patients with CNS AT/RT who were treated with radiation therapy (RT) as part of multimodality treatment regimens at a single institution (1996-2015) were reviewed. Survival outcomes were analyzed in relation to possible prognostic factors.

The 28 patients analyzed were followed up for a median 48-month period. Median progression-free survival (PFS) was 11 months, and overall survival (OS) was 57 months. Patients < 3 years old had RT delayed for a longer period after surgery (p = 0.04), and the mean RT dose to tumor bed was lower (p < 0.01) than in patients ≥ 3 years old. In multivariate analysis, a higher primary tumor bed RT dose was identified as a favorable prognostic factor for both PFS (hazard ratio [HR] = 0.85 per gray, p < 0.01) and OS (HR = 0.92 per gray, p = 0.02). In addition, an interval between surgery and RT initiation > 2 months, with disease progression observed before RT, as compared with an interval ≤ 2 months without disease progression prior to RT, was associated with worse PFS (HR = 8.50, p < 0.01) and OS (HR = 5.27, p < 0.01).

Early and aggressive RT after surgery is critical for successful disease control in AT/RT patients. Conversely, a delay in RT until disease progression is observed that leads to unfavorable outcomes 4).


In a study, Torchia et al. analyzed 191 primary Atypical teratoid rhabdoid tumor ATRTs and 10 ATRT cell lines to define the genomics and epigenomic landscape of ATRTs and identify subgroup-specific therapeutic targets. They found ATRTs segregated into three epigenetic subgroups with distinct genomic profiles, SMARCB1 genotypes, and chromatin landscape that correlated with differential cellular responses to a panel of signaling and epigenetic inhibitors. Significantly, they discovered that differential methylation of a PDGFRB-associated enhancer confers specific sensitivity of group 2 ATRT cells to dasatinib and nilotinib, and suggest that these are promising therapies for this highly lethal ATRT subtype 5).

References

1) , 5)

Torchia J, Golbourn B, Feng S, Ho KC, Sin-Chan P, Vasiljevic A, Norman JD, Guilhamon P, Garzia L, Agamez NR, Lu M, Chan TS, Picard D, de Antonellis P, Khuong-Quang DA, Planello AC, Zeller C, Barsyte-Lovejoy D, Lafay-Cousin L, Letourneau L, Bourgey M, Yu M, Gendoo DM, Dzamba M, Barszczyk M, Medina T, Riemenschneider AN, Morrissy AS, Ra YS, Ramaswamy V, Remke M, Dunham CP, Yip S, Ng HK, Lu JQ, Mehta V, Albrecht S, Pimentel J, Chan JA, Somers GR, Faria CC, Roque L, Fouladi M, Hoffman LM, Moore AS, Wang Y, Choi SA, Hansford JR, Catchpoole D, Birks DK, Foreman NK, Strother D, Klekner A, Bognár L, Garami M, Hauser P, Hortobágyi T, Wilson B, Hukin J, Carret AS, Van Meter TE, Hwang EI, Gajjar A, Chiou SH, Nakamura H, Toledano H, Fried I, Fults D, Wataya T, Fryer C, Eisenstat DD, Scheinemann K, Fleming AJ, Johnston DL, Michaud J, Zelcer S, Hammond R, Afzal S, Ramsay DA, Sirachainan N, Hongeng S, Larbcharoensub N, Grundy RG, Lulla RR, Fangusaro JR, Druker H, Bartels U, Grant R, Malkin D, McGlade CJ, Nicolaides T, Tihan T, Phillips J, Majewski J, Montpetit A, Bourque G, Bader GD, Reddy AT, Gillespie GY, Warmuth-Metz M, Rutkowski S, Tabori U, Lupien M, Brudno M, Schüller U, Pietsch T, Judkins AR, Hawkins CE, Bouffet E, Kim SK, Dirks PB, Taylor MD, Erdreich-Epstein A, Arrowsmith CH, De Carvalho DD, Rutka JT, Jabado N, Huang A. Integrated (epi)-Genomic Analyses Identify Subgroup-Specific Therapeutic Targets in CNS Rhabdoid Tumors. Cancer Cell. 2016 Dec 12;30(6):891-908. doi: 10.1016/j.ccell.2016.11.003. PubMed PMID: 27960086.
2)

Jeong JY, Suh YL, Hong SW. Atypical teratoid/rhabdoid tumor arising in pleomorphic xanthoastrocytoma: a case report. Neuropathology. 2014 Aug;34(4):398-405. PubMed PMID: 25268025.
3)

Valencia-Moya A, González-García L, Ros-López B, Acha-García T, Weil-Lara B, Obando-Pacheco P, Arráez-Sánchez MÁ. Prognosis of atypical teratoid rhabdoid tumors (AT/RT) treated with multimodal therapy protocols. Report of our series. Neurocirugia (Astur). 2015 Apr 17. pii: S1130-1473(15)00020-2. doi: 10.1016/j.neucir.2015.01.003. [Epub ahead of print] PubMed PMID: 25900785.
4)

Yang WC, Yen HJ, Liang ML, Chen HH, Lee YY, Wong TT, Hu YW, Chen YW. Role of early and aggressive post-operative radiation therapy in improving outcome for pediatric central nervous system atypical teratoid/rhabdoid tumor. Childs Nerv Syst. 2019 Apr 13. doi: 10.1007/s00381-019-04126-y. [Epub ahead of print] PubMed PMID: 30982172.

Glioma tumor microenvironment

Glioma tumor microenvironment

In a study, both U118 cell and GSC23 cell exhibited good printability and cell proliferation. Compared with 3D-U118, 3D-GSC23 had a greater ability to form cell spheroids, to secrete VEGFA, and to form tubule-like structures in vitro. More importantly, 3D-GSC23 cells had a greater power to transdifferentiate into functional endothelial cells, and blood vessels composed of tumor cells with an abnormal endothelial phenotype was observed in vivo. In summary, 3D bioprinted hydrogel scaffold provided a suitable tumor microenvironment (TME) for glioma cells and GSCs. This bioprinted model supported a novel TME for the research of glioma cells, especially GSCs in glioma vascularization and therapeutic targeting of tumor angiogenesis 1).


Important advances have been made in deciphering the microenvironment of GBMs, but its association with existing molecular subtypes and its potential prognostic role remain elusive. Jeanmougin et al. investigated the abundance of infiltrating immune and stromal cellin silico, from gene expression profiles. Two cohorts, including in-house normal brain and glioma samples (n=70) and a large sample set from The Cancer Genome Atlas (TCGA)(n=393), were combined into a single exploratory dataset. A third independent cohort (n=124) was used for validation. Tumors were clustered based on their microenvironment infiltration profiles, and associations with known GBM molecular subtypes and patient outcome were tested a posteriori in a multivariable setting. Jeanmougin et al. identified a subset of GBM samples with significantly higher abundances of most immune and stromal cell populations. This subset showed increased expression of both immune suppressor and immune effector genes compared to other GBMs and was enriched for the mesenchymal molecular subtype. Survival analyses suggested that the tumor microenvironment infiltration pattern was an independent prognostic factor for GBM patients. Among all, patients with the mesenchymal subtype with low immune and stromal infiltration had the poorest survival. By combining molecular subtyping with gene expression measures of tumor infiltration, the present work contributes to improving prognostic models in GBM 2).


Tumor-associated microglia and macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are potent immunosuppressors in the glioma tumor microenvironment (TME). Their infiltration is associated with tumor grade, progression and therapy resistance.

This resiliency of glioma stem cells (GSCs) is, in part, due to self-remodeling of their supportive niche also known as the tumor microenvironment 3) 4) 5) 6).

The tumor and the surrounding microenvironment are closely related and interact constantly. Tumors can influence the microenvironment by releasing extracellular signals, promoting tumor angiogenesis and inducing peripheral immune tolerance, while the immune cells in the microenvironment can affect the growth and evolution of cancerous cells.

The tumor microenvironment contributes to tumour heterogeneity.

Tumor microenvironment has been shown to be an important source for therapeutic targets in both adult and pediatric neoplasms.

Solid cancers develop in dynamically modified microenvironments in which they seem to hijack resident and infiltrating nontumor cells, and exploit existing extracellular matrices and interstitial fluids for their own benefit. Glioblastoma (GBM), the most malignant intrinsic glial brain tumor, hardly colonizes niches outside the central nervous system (CNS). It seems to need the unique composition of cranial microenvironment for growth and invasion as the incidence of extracranial metastasis of GBM is as low as 0.5%. Different nontumor cells (both infiltrating and resident), structures and substances constitute a semiprotected environment, partially behind the well-known blood–brain barrier, benefitting from the relatively immune privileged state of the CNS. This imposes a particular challenge on researchers and clinicians who try to tackle this disease and desire to penetrate efficiently into this shielded environment to weaken the GBM cells and cut them off from the Hinterland they are addicted to. In this chapter, we focus on how GBM interacts with the different components of its tumor microenvironment (TME), how we can target this TME as a useful contribution to the existing treatments, how we could make further progress in our understanding and interaction with this environment as a crucial step toward a better disease control in the future, and what efforts have already been taken thus far 7).


To characterize the glioma tumor microenvironment, a mixed collective of nine glioma patients underwent [18F]DPA-714-PET-MRI in addition to [18F]FET-PET-MRI. Image-guided biopsy samples were immuno-phenotyped by multiparameter flow cytometry and immunohistochemistry. In vitro autoradiography was performed for image validation and assessment of tracer binding specificity.

They found a strong relationship (r = 0.84, p = 0.009) between the [18F]DPA-714 uptake and the number and activation level of glioma-associated myeloid cells (GAMs). TSPO expression was mainly restricted to HLA-DR+ activated GAMs, particularly to tumor-infiltrating HLA-DR+ MDSCs and TAMs. [18F]DPA-714-positive tissue volumes exceeded [18F]FET-positive volumes and showed a differential spatial distribution.

[18F]DPA-714-PET may be used to non-invasively image the glioma-associated immunosuppressive TME in vivo. This imaging paradigm may also help to characterize the heterogeneity of the glioma TME with respect to the degree of myeloid cell infiltration at various disease stages. [18F]DPA-714 may also facilitate the development of new image-guided therapies targeting the myeloid-derived TME. 8).

References

1)

Wang X, Li X, Ding J, et al. 3D bioprinted glioma microenvironment for glioma vascularization [published online ahead of print, 2020 Aug 10]. J Biomed Mater Res A. 2020;10.1002/jbm.a.37082. doi:10.1002/jbm.a.37082
2)

Jeanmougin M, Håvik AB, Cekaite L, Brandal P, Sveen A, Meling TR, Ågesen TH, Scheie D, Heim S, Lothe RA, Lind GE. Improved prognostication of glioblastoma beyond molecular subtyping by transcriptional profiling of the tumor microenvironment. Mol Oncol. 2020 Mar 14. doi: 10.1002/1878-0261.12668. [Epub ahead of print] PubMed PMID: 32171051.
3)

Calabrese C, Poppleton H, Kocak M, et al. A perivascular niche for brain tumor stem cells. Cancer Cell. 2007;11(1):69-82.
4)

Cheng L, Huang Z, Zhou W, et al. Glioblastoma stem cells generate vascular pericytes to support vessel function and tumor growth. Cell. 2013;153(1):139- 152.
5)

Lathia JD, Heddleston JM, Venere M, et al. Deadly teamwork: neural cancer stem cells and the tumor microenvironment. Cell Stem Cell. 2011;8(5):482- 485.
6)

Wang L, Rahn JJ, Lun X, et al. Gamma-secretase represents a therapeutic target for the treatment of invasive glioma mediated by the p75 neurotrophin receptor. PLoS Biol. 2008;6(11):e289.
7)

De Vleeschouwer S, Bergers G. Glioblastoma: To Target the Tumor Cell or the Microenvironment? In: De Vleeschouwer S, editor. Glioblastoma [Internet]. Brisbane (AU): Codon Publications; 2017 Sep 27. Chapter 16. Available from http://www.ncbi.nlm.nih.gov/books/NBK469984/ PubMed PMID: 29251862.
8)

Zinnhardt B, Müther M, Roll W, Backhaus P, Jeibmann A, Foray C, Barca C, Döring C, Tavitian B, Dollé F, Weckesser M, Winkeler A, Hermann S, Wagner S, Wiendl H, Stummer W, Jacobs AH, Schäfers M, Grauer OM. TSPO imaging-guided characterization of the immunosuppressive myeloid tumor microenvironment in patients with malignant glioma. Neuro Oncol. 2020 Feb 12. pii: noaa023. doi: 10.1093/neuonc/noaa023. [Epub ahead of print] PubMed PMID: 32047908.

May 4 Webinar Tips and Tricks in Pituitary tumor surgery – Prof. Danny Prevedello

Topic: Tips and Tricks in Pituitary tumor surgery – Prof. Danny Prevedello

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