ATRT-SHH comprises three molecular subgroups with characteristic clinical and histopathological features and prognostic significance.

Abstract

Atypical teratoid/rhabdoid tumor (ATRT) is an aggressive central nervous system tumor characterized by loss of SMARCB1/INI1 protein expression and comprises three distinct molecular groups, ATRT-TYR, ATRT-MYC and ATRT-SHH. ATRT-SHH represents the largest molecular group and is heterogeneous with regard to age, tumor location and epigenetic profile. We, therefore, aimed to investigate if heterogeneity within ATRT-SHH might also have biological and clinical importance. Consensus clustering of DNA methylation profiles and confirmatory t-SNE analysis of 65 ATRT-SHH yielded three robust molecular subgroups, i.e., SHH-1A, SHH-1B and SHH-2. These subgroups differed by median age of onset (SHH-1A: 18 months, SHH-1B: 107 months, SHH-2: 13 months) and tumor location (SHH-1A: 88% supratentorial; SHH-1B: 85% supratentorial; SHH-2: 93% infratentorial, often extending to the pineal region). Subgroups showed comparable SMARCB1 mutational profiles, but pathogenic/likely pathogenic SMARCB1 germline variants were over-represented in SHH-2 (63%) as compared to SHH-1A (20%) and SHH-1B (0%). Protein expression of proneural marker ASCL1 (enriched in SHH-1B) and glial markers OLIG2 and GFAP (absent in SHH-2) as well as global mRNA expression patterns differed, but all subgroups were characterized by overexpression of SHH as well as Notch pathway members. In a Drosophila model, knockdown of Snr1 (the fly homologue of SMARCB1) in hedgehog activated cells not only altered hedgehog signaling, but also caused aberrant Notch signaling and formation of tumor-like structures. Finally, on survival analysis, molecular subgroup and age of onset (but not ASCL1 staining status) were independently associated with overall survival, older patients (> 3 years) harboring SHH-1B experiencing relatively favorable outcome. In conclusion, ATRT-SHH comprises three subgroups characterized by SHH and Notch pathway activation, but divergent molecular and clinical features. Our data suggest that molecular subgrouping of ATRT-SHH has prognostic relevance and might aid to stratify patients within future clinical trials.

• Authors: Aniello Federico, Christian Thomas, Katarzyna Miskiewicz, Niklas Woltering, Francesca Zin, Karolina Nemes, Brigitte Bison, Pascal D Johann, Debra Hawes, Susanne Bens, Uwe Kordes, Steffen Albrecht, Hildegard Dohmen, Peter Hauser, Kathy Keyvani, Frank K H van Landeghem, Eva Løbner Lund, David Scheie, Christian Mawrin, Camelia-Maria Monoranu, Benedicte Parm Ulhøi, Torsten Pietsch, Harald Reinhard, Markus J Riemenschneider, Astrid Sehested, David Sumerauer, Reiner Siebert, Werner Paulus, Michael C Frühwald, Marcel Kool, Martin Hasselblatt
• Journal: Acta neuropathologica (Acta Neuropathol) Vol. 143 Issue 6 Pg. 697-711 (06 2022) ISSN: 1432-0533 [Electronic] Germany
• PMID: 35501487 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2022. The Author(s).

Chemical References

• Hedgehog Proteins
• SHH protein, human
• SMARCB1 Protein

Topics

• Central Nervous System Neoplasms (genetics)
• DNA Methylation
• Hedgehog Proteins (genetics, metabolism)
• Humans
• Neoplasms, Neuroepithelial (genetics)
• Prognosis
• Rhabdoid Tumor (genetics)
• SMARCB1 Protein (genetics, metabolism)
• Teratoma (genetics)