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Dr Timothy Ritzmann's Outputs (26)

European standard clinical practice recommendations for newly diagnosed ependymoma of childhood and adolescence (2025)
Journal Article
Simon, A. R. S., Ritzmann, T. A., Obrecht-Sturm, D., Benesch, M., Timmermann, B., Leblond, P., Kilday, J.-P., Poggi, G., Thorp, N., Massimino, M., van Veelen, M.-L., Schuhmann, M., Thomale, U.-W., Tippelt, S., Schüller, U., Rutkowski, S., Grundy, R. G., Bolle, S., Fernández-Teijeiro, A., & Pajtler, K. W. (2025). European standard clinical practice recommendations for newly diagnosed ependymoma of childhood and adolescence. EJC Paediatric Oncology, 5, Article 100227. https://doi.org/10.1016/j.ejcped.2025.100227

Ependymomas are tumors of glial origin representing the second most common malignant brain tumors of childhood. Peak incidence in childhood is under 3 years of age. Most paediatric ependymomas arise intracranially and are molecularly divided into fou... Read More about European standard clinical practice recommendations for newly diagnosed ependymoma of childhood and adolescence.

Cognitive Outcomes in Children Treated for Ependymoma Diagnosed Under 36 Months: A Systematic Review (2025)
Journal Article
Thomas, S., Morley, E., Ritzmann, T., Clayton, C., Powers, K., Airdrie, J., Robinson, L., Fifield, K., Packham, A., Oprandi, M. C., Lui, J., Whitfield, G., Thorp, N., Limond, J., & Grundy, R. (in press). Cognitive Outcomes in Children Treated for Ependymoma Diagnosed Under 36 Months: A Systematic Review. Pediatric Blood and Cancer, Article e31588. https://doi.org/10.1002/pbc.31588

It is crucial to understand the morbidity associated with treatments for young children with ependymoma given this is a high incidence age group also known to be at risk of poorer cognitive outcomes. This review aimed to identify the quality of exist... Read More about Cognitive Outcomes in Children Treated for Ependymoma Diagnosed Under 36 Months: A Systematic Review.

A review calling for research directed at early detection of childhood cancers: The clinical, scientific, and economic arguments for population screening and surveillance (2024)
Journal Article
Apps, J., Ritzmann, T. A., Liu, J., Shanmugavadivel, D., Halsey, C., Pritchard Jones, K., Atun, R., Oliver, K., Vedhara, K., Ball-Gamble, A., Ranasinghe, N., Polanco, A., Adamski, J., Green, A. L., & Walker, D. A. (2024). A review calling for research directed at early detection of childhood cancers: The clinical, scientific, and economic arguments for population screening and surveillance. European Journal of Cancer, 4, Article 100191. https://doi.org/10.1016/j.ejcped.2024.100191

Childhood cancers are increasingly recognised as disorders of tissue growth and development, through early life into adulthood. A rising proportion are currently considered to be related to a familial predisposition or associated with identified gene... Read More about A review calling for research directed at early detection of childhood cancers: The clinical, scientific, and economic arguments for population screening and surveillance.

Multi-omic approach identifies hypoxic tumor-associated myeloid cells that drive immunobiology of high-risk pediatric ependymoma. (2023)
Journal Article
Griesinger, A. M., Riemondy, K., Eswaran, N., Donson, A. M., Willard, N., Prince, E. W., Paine, S. M. L., Bowes, G., Rheaume, J., Chapman, R. J., Ramage, J., Jackson, A., Grundy, R. G., Foreman, N. K., & Ritzmann, T. A. (2023). Multi-omic approach identifies hypoxic tumor-associated myeloid cells that drive immunobiology of high-risk pediatric ependymoma. iScience, 26(9), Article 107585. https://doi.org/10.1016/j.isci.2023.107585

Ependymoma (EPN) is a devastating childhood brain tumor. Single-cell analyses have illustrated the cellular heterogeneity of EPN tumors, identifying multiple neoplastic cell states including a mesenchymal-differentiated subpopulation which characteri... Read More about Multi-omic approach identifies hypoxic tumor-associated myeloid cells that drive immunobiology of high-risk pediatric ependymoma..

Significant increase of high-risk chromosome 1q gain and 6q loss at recurrence in posterior fossa group A ependymoma: a multicenter study (2023)
Journal Article
Donson, A. M., Bertrand, K. C., Riemondy, K. A., Gao, D., Zhuang, Y., Sanford, B., Norris, G. A., Chapman, R. J., Fu, R., Willard, N., Griesinger, A. M., de Sousa, G. R., Amani, V., Grimaldo, E., Hankinson, T. C., Booker, F., Sill, M., Grundy, R. G., Pajtler, K. W., Ellison, D. W., …Ritzmann, T. A. (2023). Significant increase of high-risk chromosome 1q gain and 6q loss at recurrence in posterior fossa group A ependymoma: a multicenter study. Neuro-Oncology, 25(10), 1854-1867. https://doi.org/10.1093/neuonc/noad096

Background
Ependymoma (EPN) posterior fossa group A (PFA) has the highest rate of recurrence and the worst prognosis of all EPN molecular groups. At relapse, it is typically incurable even with re-resection and re-irradiation. The biology of recurre... Read More about Significant increase of high-risk chromosome 1q gain and 6q loss at recurrence in posterior fossa group A ependymoma: a multicenter study.

Optimising biomarkers for accurate ependymoma diagnosis, prognostication and stratification within International Clinical Trials: A BIOMECA study (2023)
Journal Article
Chapman, R. J., Ghasemi, D. R., Andreiuolo, F., Zschernack, V., Tauziede Espariat, A., Buttarelli, F. R., Giangaspero, F., Grill, J., Haberler, C., Paine, S. M., Scott, I., Jacques, T. S., Sill, M., Pfister, S., Kilday, J.-P., Leblond, P., Massimino, M., Witt, H., Modena, P., Varlet, P., …Biomarkers of Ependymoma in Childhood and Adolescence (BIOMECA) Consortium. (2023). Optimising biomarkers for accurate ependymoma diagnosis, prognostication and stratification within International Clinical Trials: A BIOMECA study. Neuro-Oncology, 25(10), 1871–1882. https://doi.org/10.1093/neuonc/noad055

Background Accurate identification of brain tumour molecular subgroups is increasingly important. We aimed to establish the most accurate and reproducible ependymoma subgroup biomarker detection techniques, across 147 cases from International Society... Read More about Optimising biomarkers for accurate ependymoma diagnosis, prognostication and stratification within International Clinical Trials: A BIOMECA study.

Spatial transcriptomic analysis delineates epithelial and mesenchymal subpopulations and transition stages in childhood ependymoma (2022)
Journal Article
Fu, R., Norris, G. A., Willard, N., Griesinger, A. M., Riemondy, K. A., Amani, V., Grimaldo, E., Harris, F., Hankinson, T. C., Mitra, S., Ritzmann, T. A., Grundy, R. R., Foreman, N. K., & Donson, A. M. (2023). Spatial transcriptomic analysis delineates epithelial and mesenchymal subpopulations and transition stages in childhood ependymoma. Neuro-Oncology, 25(4), 786-798. https://doi.org/10.1093/neuonc/noac219

Background The diverse cellular constituents of childhood brain tumor ependymoma, recently revealed by single cell RNA-sequencing, may underly therapeutic resistance. Here we use spatial transcriptomics to further advance our understanding of the tum... Read More about Spatial transcriptomic analysis delineates epithelial and mesenchymal subpopulations and transition stages in childhood ependymoma.

Toward Improved Diagnosis Accuracy and Treatment of Children, Adolescents, and Young Adults With Ependymoma: The International SIOP Ependymoma II Protocol (2022)
Journal Article
Leblond, P., Massimino, M., English, M., Ritzmann, T. A., Gandola, L., Calaminus, G., Thomas, S., Pérol, D., Gautier, J., Grundy, R. G., & Frappaz, D. (2022). Toward Improved Diagnosis Accuracy and Treatment of Children, Adolescents, and Young Adults With Ependymoma: The International SIOP Ependymoma II Protocol. Frontiers in Neurology, 13, Article 887544. https://doi.org/10.3389/fneur.2022.887544

Background: The clinical management of ependymoma in childhood and adolescence is complex and the clinicobiopathological correlates of outcome remain poorly understood. This international SIOP Ependymoma II (SIOP EPII) trial aims to improve the outco... Read More about Toward Improved Diagnosis Accuracy and Treatment of Children, Adolescents, and Young Adults With Ependymoma: The International SIOP Ependymoma II Protocol.

Recurrent ACVR1 mutations in posterior fossa ependymoma (2022)
Journal Article
Pratt, D., Lucas, C.-H. G., Selvam, P. P., Abdullaev, Z., Ketchum, C., Quezado, M., Armstrong, T. S., Gilbert, M. R., Papanicolau-Sengos, A., Raffeld, M., Choo-Wosoba, H., Chan, P., Whipple, N., Nasrallah, M., Santi, M., Ramaswamy, V., Giannini, C., Ritzmann, T. A., Grundy, R. G., Burford, A., …Aldape, K. (2022). Recurrent ACVR1 mutations in posterior fossa ependymoma. Acta Neuropathologica, 144, 373-376. https://doi.org/10.1007/s00401-022-02435-2

Phase II study of intravenous etoposide in patients with relapsed ependymoma (CNS 2001 04) (2022)
Journal Article
Apps, J. R., Maycock, S., Ellison, D. W., Jaspan, T., Ritzmann, T. A., Macarthur, D., Mallucci, C., Wheatley, K., Veal, G. J., Grundy, R. G., & Picton, S. (2022). Phase II study of intravenous etoposide in patients with relapsed ependymoma (CNS 2001 04). Neuro-Oncology Advances, 4(1), Article vdac053. https://doi.org/10.1093/noajnl/vdac053

Background
Relapsed ependymoma has a dismal prognosis, and the role of chemotherapy at relapse remains unclear. This study prospectively evaluated the efficacy of intensive intravenous (IV) etoposide in patients less than 21 years of age with relaps... Read More about Phase II study of intravenous etoposide in patients with relapsed ependymoma (CNS 2001 04).

SIOP Ependymoma I: Final results, long term follow-up and molecular analysis of the trial cohort: A BIOMECA Consortium Study (2022)
Journal Article
Ritzmann, T. A., Chapman, R. J., Kilday, J.-P., Thorp, N., Modena, P., Dineen, R. A., Macarthur, D., Mallucci, C., Jaspan, T., Pajtler, K. W., Giagnacovo, M., Jacques, T., Paine, S., Ellison, D., Bouffet, E., & Grundy, R. G. (2022). SIOP Ependymoma I: Final results, long term follow-up and molecular analysis of the trial cohort: A BIOMECA Consortium Study. Neuro-Oncology, 24(6), 936–948. https://doi.org/10.1093/neuonc/noac012

Background
SIOP Ependymoma I was a non-randomised trial assessing event free and overall survival (EFS/OS) of non-metastatic intracranial ependymoma in children aged 3 to 21 years treated with a staged management strategy. A further aim was to asses... Read More about SIOP Ependymoma I: Final results, long term follow-up and molecular analysis of the trial cohort: A BIOMECA Consortium Study.

Multicentre service evaluation of presentation of newly diagnosed cancers and type 1 diabetes in children in the UK during the COVID-19 pandemic (2021)
Journal Article
Williams, G., McLean, R., Liu, J. F., Ritzmann, T. A., Dandapani, M., Shanmugavadivel, D., Sachdev, P., Brougham, M., Mitchell, R. T., Conway, N. T., Law, J., Cunnington, A., Ogunnaike, G., Brougham, K., Bayman, E., & Walker, D. (2021). Multicentre service evaluation of presentation of newly diagnosed cancers and type 1 diabetes in children in the UK during the COVID-19 pandemic. BMJ Paediatrics Open, 5(1), Article e001078. https://doi.org/10.1136/bmjpo-2021-001078

Background The COVID-19 pandemic led to changes in patterns of presentation to emergency departments. Child health professionals were concerned that this could contribute to the delayed diagnosis of life-threatening conditions, including childhood ca... Read More about Multicentre service evaluation of presentation of newly diagnosed cancers and type 1 diabetes in children in the UK during the COVID-19 pandemic.

EPEN-04. SIOP EPENDYMOMA I: FINAL RESULTS, LONG TERM FOLLOW-UP AND MOLECULAR ANALYSIS OF THE TRIAL COHORT: A BIOMECA CONSORTIUM STUDY (2021)
Journal Article
Ritzmann, T. A., Chapman, R. J., Macarthur, D., Mallucci, C., Kilday, J.-P., Thorp, N., Modena, P., Giagnacovo, M., Dineen, R., Jaspan, T., Pajtler, K. W., Jacques, T. S., Paine, S. M. L., Ellison, D. W., Bouffet, E., & Grundy, R. G. (2021). EPEN-04. SIOP EPENDYMOMA I: FINAL RESULTS, LONG TERM FOLLOW-UP AND MOLECULAR ANALYSIS OF THE TRIAL COHORT: A BIOMECA CONSORTIUM STUDY. Neuro-Oncology, 23(Supplement 1), i14. https://doi.org/10.1093/neuonc/noab090.054

Introduction
Surgery and radiotherapy are established childhood ependymoma treatments. The efficacy of chemotherapy has been debated. We report final results of the SIOP Ependymoma I trial, with 12-year follow-up, in the context of a post-hoc analys... Read More about EPEN-04. SIOP EPENDYMOMA I: FINAL RESULTS, LONG TERM FOLLOW-UP AND MOLECULAR ANALYSIS OF THE TRIAL COHORT: A BIOMECA CONSORTIUM STUDY.

EPEN-11. TUMOR DIFFERENTIATION IMPACTS THE BIOLOGY OF RECURRENCE IN CHILDHOOD POSTERIOR FOSSA EPENDYMOMA (2021)
Journal Article
Donson, A., Ritzmann, T., Willard, N., Griesinger, A., Amani, V., Harris, F., Grimaldo, E., Sanford, B., Riemondy, K., Hankinson, T., Grundy, R., & Foreman, N. (2021). EPEN-11. TUMOR DIFFERENTIATION IMPACTS THE BIOLOGY OF RECURRENCE IN CHILDHOOD POSTERIOR FOSSA EPENDYMOMA. Neuro-Oncology, 23(Supplement 1), i15-i16. https://doi.org/10.1093/neuonc/noab090.061

Ependymoma (EPN) of childhood is curable in only 50% of cases, with recurrences in the remainder that are refractory to treatment. In recent years significant advances have been made in understanding the molecular and cellular biology of EPN. Recent... Read More about EPEN-11. TUMOR DIFFERENTIATION IMPACTS THE BIOLOGY OF RECURRENCE IN CHILDHOOD POSTERIOR FOSSA EPENDYMOMA.

EPEN-08. THE TREM1 POSITIVE HYPOXIC MYELOID SUBPOPULATION IN POSTERIOR FOSSA EPENDYMOMA (2021)
Journal Article
Willard, N., Donson, A., Ritzmann, T., Grundy, R., Jackson, A., Hankinson, T., Griesinger, A., & Foreman, N. (2021). EPEN-08. THE TREM1 POSITIVE HYPOXIC MYELOID SUBPOPULATION IN POSTERIOR FOSSA EPENDYMOMA. Neuro-Oncology, 23(Supplement 1), i15. https://doi.org/10.1093/neuonc/noab090.058

We have previously shown the importance of immune factors in posterior fossa ependymoma (PF EPN). Recently, we found eight transcriptionally unique subpopulations of myeloid cells infiltrating PF EPN with one population particularly enriched in PFA1... Read More about EPEN-08. THE TREM1 POSITIVE HYPOXIC MYELOID SUBPOPULATION IN POSTERIOR FOSSA EPENDYMOMA.

EPEN-07. SINGLE-CELL RNA SEQUENCING IDENTIFIES A UNIQUE MYELOID SUBPOPULATION ASSOCIATED WITH MESENCHYMAL TUMOR SUBPOPULATION IN POOR OUTCOME PEDIATRIC EPENDYMOMA (2021)
Journal Article
Griesinger, A., Riemondy, K., Donson, A., Willard, N., Prince, E., Harris, F., Amani, V., Grimaldo, E., Hankinson, T., Grundy, R., Jackson, A., Foreman, N., & Ritzmann, T. (2021). EPEN-07. SINGLE-CELL RNA SEQUENCING IDENTIFIES A UNIQUE MYELOID SUBPOPULATION ASSOCIATED WITH MESENCHYMAL TUMOR SUBPOPULATION IN POOR OUTCOME PEDIATRIC EPENDYMOMA. Neuro-Oncology, 23(Supplement 1), i14-i15. https://doi.org/10.1093/neuonc/noab090.057

We have previously shown immune gene phenotype variations between posterior fossa ependymoma subgroups. PFA1 tumors chronically secrete IL-6, which induces secretion of myeloid cell IL-8 and pushes the infiltrating myeloid cells to an immune suppress... Read More about EPEN-07. SINGLE-CELL RNA SEQUENCING IDENTIFIES A UNIQUE MYELOID SUBPOPULATION ASSOCIATED WITH MESENCHYMAL TUMOR SUBPOPULATION IN POOR OUTCOME PEDIATRIC EPENDYMOMA.

Assessment of Cannabidiol and ∆9-Tetrahydrocannabiol in Mouse Models of Medulloblastoma and Ependymoma (2021)
Journal Article
Andradas, C., Byrne, J., Kuchibhotla, M., Ancliffe, M., Jones, A. C., Carline, B., Hii, H., Truong, A., Storer, L. C. D., Ritzmann, T. A., Grundy, R. G., Gottardo, N. G., & Endersby, R. (2021). Assessment of Cannabidiol and ∆9-Tetrahydrocannabiol in Mouse Models of Medulloblastoma and Ependymoma. Cancers, 13, Article 330. https://doi.org/10.3390/cancers13020330

Children with medulloblastoma and ependymoma are treated with a multidisciplinary approach that incorporates surgery, radiotherapy, and chemotherapy; however, overall survival rates for patients with high-risk disease remain unsatisfactory. Data indi... Read More about Assessment of Cannabidiol and ∆9-Tetrahydrocannabiol in Mouse Models of Medulloblastoma and Ependymoma.

Epen-23. A computational analysis of the tumour immune microenvironment in paediatric ependymoma (2020)
Presentation / Conference Contribution
Ritzmann, T., Lourdusamy, A., Jackson, A., Storer, L., Donson, A., Griesinger, A., Foreman, N., Rogers, H., & Grundy, R. Epen-23. A computational analysis of the tumour immune microenvironment in paediatric ependymoma

Ependymoma is the third commonest childhood brain tumour. Relapse is frequent, often fatal and current therapeutic strategies are inadequate. Previous ependymoma research describes an immunosuppressive environment with T-cell exhaustion, indicating a... Read More about Epen-23. A computational analysis of the tumour immune microenvironment in paediatric ependymoma.

Epen-22. Single-cell RNA sequencing identifies upregulation of IKZF1 in PFA2 myeloid subpopulation driving an anti-tumor phenotype (2020)
Presentation / Conference Contribution
Griesinger, A., Prince, E., Donson, A., Riemondy, K., Ritzman, T., Harris, F., Amani, V., Handler, M., Hankinson, T., Grundy, R., Jackson, A., & Foreman, N. Epen-22. Single-cell RNA sequencing identifies upregulation of IKZF1 in PFA2 myeloid subpopulation driving an anti-tumor phenotype

We have previously shown immune gene phenotype variations between posterior fossa ependymoma subgroups. PFA1 tumors chronically secrete IL-6, which pushes the infiltrating myeloid cells to an immune suppressive function. In contrast, PFA2 tumors have... Read More about Epen-22. Single-cell RNA sequencing identifies upregulation of IKZF1 in PFA2 myeloid subpopulation driving an anti-tumor phenotype.