27 research outputs found
Biomolecular characterization of metastatic medulloblastoma and study of telomere lengthening control
Medulloblastoma (MDB) is a malignant embryonic brain tumor and occurs typically in pediatric patients. Medulloblastoma cells can disseminate through the cerebrospinal fluid in the leptomeningeal space; approximately 30% of children present metastasis at the onset and no gold standard treatment has been defined for these patients. Genetic, epigenetic and molecular analyses identified four molecular subgroups (WNT, SHH, group 3 and group 4), associated with prognostic stratification of patients; however, previous works in literature included only small amount of metastatic cases, not analyzed independently from the non-metastatic counterpart. Furthermore, recent studies evidenced that mechanisms of telomeres elongation can be activated in pediatric brain tumours and telomeres maintenance was enriched in SHH and group 3 non-metastatic MDB; however, elongation of telomeres was not previously investigated in metastatic medulloblastomas.
Therefore, our aim is to characterize a series of 39 pediatric MDB, selected from a cohort of 60, with leptomeningeal dissemination at the onset, studying molecular features involved in malignancy, metastasis, telomeres elongation and senescence escape. We analyzed several biomarkers and we correlated results to outcome of patients, evaluating the prognostic relevance of molecular biomarkers and subgroups. Furthermore, we analyzed the activation of mechanisms involved in control of telomeres lengthening, in order to figure out if telomeres elongation could have a role in metastatic medulloblastomas.
We show that distribution of metastatic MDB into four molecular subgroups is highly similar to the distribution of non-metastatic cases, reflecting a high molecular heterogeneity; interestingly, our molecular subgrouping system defines high-risk (group SHH, 3 and 4) and standard-risk (group WNT and Not Classifiable) patients. Furthermore, we evidence that FSTL5 over-expression is associated exclusively with groups 3/4 and with poor outcome of patients, highlighting that FSTL5 can be used to better define molecular subgroups, prognosis and risk stratification of metastatic medulloblastomas.
In addition, we analyzed H3.3 and ATRX mutations, involved in activation of the Alternative Lengthening of Telomeres (ALT) pathway, and the mutation and methylation status of TERT promoter, involved in telomerase reactivation. We evidence that metastatic MDB activate elongation of telomeres both via telomerase (14%) and via ALT mechanism (27%), triggered by ATRX mutations; interestingly, ALT pathway is highly activated in our cohort compared to MDB previously analysed in literature (<5%), highlighting the differences between metastatic and non-metastatic tumors in control of telomeres elongation and senescence escape. Furthermore, metastatic MDB show a higher reactivation of telomerase compared to pHGG (0%), triggered by TERT promoter mutations in combination with hyper-methylation. Our findings suggest that immortalization of tumor cells in metastatic MDB is a common process to escape from senescence and characterizes all molecular subgroups.
In conclusion, our results contribute to improve the current characterization of pediatric patients with metastatic medulloblastoma; however, further studies will be necessary to increase the number of cases and to analyze, with statistical significance, the molecular subgroups, FSTL5 expression, and telomeres elongation, which could be used to “personalize” treatments or develop targeted therapies, reducing the side effects of the current therapeutic protocols
Biomolecular characterization of metastatic medulloblastoma and study of telomere lengthening control
Medulloblastoma (MDB) is a malignant embryonic brain tumor and occurs typically in pediatric patients. Medulloblastoma cells can disseminate through the cerebrospinal fluid in the leptomeningeal space; approximately 30% of children present metastasis at the onset and no gold standard treatment has been defined for these patients. Genetic, epigenetic and molecular analyses identified four molecular subgroups (WNT, SHH, group 3 and group 4), associated with prognostic stratification of patients; however, previous works in literature included only small amount of metastatic cases, not analyzed independently from the non-metastatic counterpart. Furthermore, recent studies evidenced that mechanisms of telomeres elongation can be activated in pediatric brain tumours and telomeres maintenance was enriched in SHH and group 3 non-metastatic MDB; however, elongation of telomeres was not previously investigated in metastatic medulloblastomas.
Therefore, our aim is to characterize a series of 39 pediatric MDB, selected from a cohort of 60, with leptomeningeal dissemination at the onset, studying molecular features involved in malignancy, metastasis, telomeres elongation and senescence escape. We analyzed several biomarkers and we correlated results to outcome of patients, evaluating the prognostic relevance of molecular biomarkers and subgroups. Furthermore, we analyzed the activation of mechanisms involved in control of telomeres lengthening, in order to figure out if telomeres elongation could have a role in metastatic medulloblastomas.
We show that distribution of metastatic MDB into four molecular subgroups is highly similar to the distribution of non-metastatic cases, reflecting a high molecular heterogeneity; interestingly, our molecular subgrouping system defines high-risk (group SHH, 3 and 4) and standard-risk (group WNT and Not Classifiable) patients. Furthermore, we evidence that FSTL5 over-expression is associated exclusively with groups 3/4 and with poor outcome of patients, highlighting that FSTL5 can be used to better define molecular subgroups, prognosis and risk stratification of metastatic medulloblastomas.
In addition, we analyzed H3.3 and ATRX mutations, involved in activation of the Alternative Lengthening of Telomeres (ALT) pathway, and the mutation and methylation status of TERT promoter, involved in telomerase reactivation. We evidence that metastatic MDB activate elongation of telomeres both via telomerase (14%) and via ALT mechanism (27%), triggered by ATRX mutations; interestingly, ALT pathway is highly activated in our cohort compared to MDB previously analysed in literature (<5%), highlighting the differences between metastatic and non-metastatic tumors in control of telomeres elongation and senescence escape. Furthermore, metastatic MDB show a higher reactivation of telomerase compared to pHGG (0%), triggered by TERT promoter mutations in combination with hyper-methylation. Our findings suggest that immortalization of tumor cells in metastatic MDB is a common process to escape from senescence and characterizes all molecular subgroups.
In conclusion, our results contribute to improve the current characterization of pediatric patients with metastatic medulloblastoma; however, further studies will be necessary to increase the number of cases and to analyze, with statistical significance, the molecular subgroups, FSTL5 expression, and telomeres elongation, which could be used to “personalize” treatments or develop targeted therapies, reducing the side effects of the current therapeutic protocols
FSTL5 expression is a marker of Group C metastatic medulloblastomas
INTRODUCTION: Medulloblastoma (MB) is the most commonmalignant
brain tumor in children. Four different molecular subgroups are recognized,
which differ in gene expression, genomic aberrations, histology, demographics
and survival:WNT and SHH groups, having specific mutations in the homonymous
pathway, and groups C and D having several genetic alternations
not specific to a single pathway. The gene for follistatin-like protein 5, FSTL5,
is overexpressed in nonSHH/nonWNT MBs poorly characterized. Highexpression
of FSTL5 is significantly associated with reduced event-free and
overall survival in non-WNT/non-SHHMBs. The major aim of this project is
to study the FSTL5 expression level in pediatric MBs with metastasis at the
onset. METHOD: We investigated the protein expression of biomarkers involved
in metastatic pathways by IHC and FSTL5 expression level by
RT-PCR in 26 metastatic MBs samples and correlated these data with the outcomes
by Kaplan-Meier statistic analysis. RESULTS: 83% of Group C MBs
showed high level of FSTL5 while none of these presented down-expression.
Low-expression level of FSTL5 was find in 60% of SHH MBs and none
showed over-expression. Kaplan-Meier test revealed that, in our cohort, highexpression
ofFSTL5didnot correlatewithworse outcomewhile lowexpression
of FSTL5 was associated with good prognosis and the co-presence of FSTL5
with other biomarkers correlated with poorer prognosis. CONCLUSION:
FSTL5 is a marker of Group C in medulloblastomas with metastasis at the
onset and the results highlighted decreased FSTL5 expression as a marker of
good prognosis. Group C MBs have characteristic molecular features that
confirm the poorest outcome also inMBs with metastasis at the onset
Paediatric-type diffuse high-grade gliomas in the 5th CNS WHO Classification
As a relevant element of novelty, the fifth CNS WHO Classification highlights the distinctive pathobiology underlying gliomas arising primarily in children by recognizing for the first time the families of paediatric-type diffuse gliomas, both high-grade and low-grade. This review will focus on the family of paediatric-type diffuse high-grade gliomas, which includes four tumour types: 1) Diffuse midline glioma H3 K27-altered; 2) Diffuse hemispheric glioma H3 G34-mutant; 3) Diffuse paediatric-type high-grade glioma H3-wildtype and IDH-wildtype; and 4) Infant-type hemispheric glioma. The essential and desirable diagnostic criteria as well as the entities entering in the differential will be discussed for each tumour type. A special focus will be given on the issues encountered in the daily practice, especially regarding the diagnosis of the diffuse paediatric-type high-grade glioma H3-wildtype and IDH-wildtype. The advantages and the limits of the multiple molecular tests which may be utilised to define the entities of this tumour family will be evaluated in each diagnostic context
Letter to the editors: pathogenetic analysis of sinonasal teratocarcinosarcomas reveal actionable β-catenin overexpression and a β-catenin mutation
We read with great interest the article “Pathogenetic Analysis of Sinonasal Teratocarcinosarcomas Reveal Actionable β- Catenin Overexpression and a β-Catenin Mutation” by Birkeland et al.1 In the article, the authors performed targeted exome sequencing on an index Sinonasal Teratocarcinosarcoma (SNTCS) specimen and identified an activating mutation in the β-catenin gene (CTNNB1, c.134C > T, p.S45F). In addition, they confirmed β-catenin overexpression and nuclear localization via immunohistochemistry in the index tumor and in a subsequent case. Based on their findings, the authors suggested “a role for the Wnt/β-catenin pathway in SNTCS tumorigenesis,” postulated that “this mutation is a potential genetic driver mutation and an alluring prospect for treatment using inhibitors of the Wnt/β-catenin pathway” and underlined the importance “to screen for p.S45F mutations and other mutations/aberrations in β-catenin in other teratocarcinosarcoma specimens to identify if this is a common driver mutation in these tumors.
Biomolecular Analysis of Pediatric Medulloblastoma and Prognostic Relevance of FSTL5 Expression: A Single-Center Study
Distribution and prognostic impact of molecular subgroups in a homogeneously treated series of metastatic medulloblastoma
Medulloblastoma (MDB) is the most common malignant paediatric brain
tumor. Prognostic system based on clinical parameters and histopathological
variants is commonly used in clinical practice. Four different molecular subgroups
are recognized: WNT and SHH, having specific homonymous
pathwayalterations;Cand D, havingseveral genetic alterationsand associated
to a worse outcome, but the system has not been prospectively validated in
metastatic cohorts. Purpose of this studywasto evaluate distribution andprognostic
impact of the four molecular subgroups in 47 MDB metastatic at the
onset, homogenously treated in a single institution (Gandola et al, JCO
2009). Subgroup biomarkers were investigated by IHC, RT-PCR, mRNA sequencing,
FISH; results were correlated with patient outcomes by
Kaplan-Meier. We identify 11% WNT with nuclear b-catenin, 19% SHH,
26%groupCand15%group D;29%were unclassifiable (NC) having heterogeneous
biomarkers. MYC amplification was more frequent (32.5%) compared
to MYCN (2.7%). WNT and NC groups showed longer (not
significant) OSand PFS compared to SHH,Cand D. Furthermore, low expression
of FSTL5 was associated with good prognosis (OS rate 90%, PFS rate
100%), while FSTL5 higher expression correlate with worse outcome (OS
and PFS rate 66%); difference was statistically significant (p ÂĽ 0,05). We
have previously shown that histological variants maintain prognostic value
in metastatic MDB; on the opposite, molecular sub-grouping is inefficient to
allow a better risk stratification in our metastatic MDB cohort; furthermore,
FSTL5 gene expression might be used in metastatic MDB as prognostic
factor to better define patient outcome
Improvement of the Collection, Maintenance, and Analysis of Neoplastic Cells from Urine Specimens with the Use of CytoMatrix
Urine cytology is a non-invasive test used in combination with cystoscopy for screening and follow-up of urothelial carcinoma (UC). Although cytology can be used to efficiently identify high-grade UC, it has a lower accuracy for the diagnosis of low-grade UC or patients with presence of atypical urothelial cells (AUC). For these reasons, ancillary tests have been added to urine cytology in order to improve the accuracy. However, the poor abundance of neoplastic cells in most samples and the absence of a “tissue-like” structure remains a major challenge. We used a novel synthetic support called CytoMatrix which has the property of capturing and storing cells and micro-macro aggregates within its three-dimensional structure. The urine specimens were obtained from 12 patients: 6 with suspected urothelial neoplasia (low- and high-grade) and 6 with AUC or non-neoplastic samples. The first step is the urine samples preparation, through several centrifugation passages; the second step consists in absorbing cells on the CytoMatrix, and in the subsequent formalin fixation, standard processing and paraffin embedding to prepare FFPE-CytoMatrix block. In the final step, sections are consecutively cut, stained with hematoxylin-eosin (H&E), and analyzed via UroVysion FISH and immunohistochemistry (IHC). Using our simple and reliable protocol, we can improve the quality of urine specimens, allowing a better collection, maintenance, and analysis of cells, with the advantage of using ancillary tests to support cytological diagnosis and the advantage of storing cellular material in a FFPE-CytoMatrix block