Medulloblastoma: From Molecular Subgroups to Molecular Targeted Therapies.

Brain tumors are the leading cause of cancer-related death in children, and medulloblastoma (MB) is the most common malignant pediatric brain tumor. Advances in surgery, radiation, and chemotherapy have improved the survival of MB patients. But despite these advances, 25-30% of patients still die from the disease, and survivors suffer severe long-term side effects from the aggressive therapies they receive. Although MB is often considered a single disease, molecular profiling has revealed a significant degree of heterogeneity, and there is a growing consensus that MB consists of multiple subgroups with distinct driver mutations, cells of origin, and prognosis. Here, we review recent progress in MB research, with a focus on the genes and pathways that drive tumorigenesis, the animal models that have been developed to study tumor biology, and the advances in conventional and targeted therapy.

Evolution of neurosurgical advances and nuances in medulloblastoma therapy.

Medulloblastoma, the most common malignant brain tumor in children, presents a complex treatment challenge due to its propensity for infiltrative growth within the posterior fossa and its potential attachment to critical anatomical structures. Central to the management of medulloblastoma is the surgical resection of the tumor, which is a key determinant of patient prognosis. However, the extent of surgical resection (EOR), ranging from gross total resection (GTR) to subtotal resection (STR) or even biopsy, has been the subject of extensive debate and investigation within the medical community. Today, the impact of neurosurgical EOR on the prognosis of medulloblastoma patients remains a complex and evolving area of investigation. The conflicting findings in the literature, the challenges posed by critical surrounding anatomical structures, the potential for surgical complications and neurologic morbidity, and the nuanced interactions with molecular subgroups all contribute to the complexity of this issue. As the field continues to advance, the imperative to strike a delicate balance between maximizing resection and preserving quality of life remains central to the management of medulloblastoma patients.

Clinical Prognostic Implications of Wnt Hub Genes Expression in Medulloblastoma.

Medulloblastoma is the most common type of pediatric malignant primary brain tumor, and about one-third of patients die due to disease recurrence and most survivors suffer from long-term side effects. MB is clinically, genetically, and epigenetically heterogeneous and subdivided into at least four molecular subgroups: WNT, SHH, Group 3, and Group 4. We evaluated common differentially expressed genes between a Brazilian RNA-seq GSE181293 dataset and microarray GSE85217 dataset cohort of pediatric MB samples using bioinformatics methodology in order to identify hub genes of the molecular subgroups based on PPI network construction, survival and functional analysis. The main finding was the identification of five hub genes from the WNT subgroup that are tumor suppressors, and whose lower expression is related to a worse prognosis for MB patients. Furthermore, the common genes correlated with the five tumor suppressors participate in important pathways and processes for tumor initiation and progression, as well as development and differentiation, and some of them control cell stemness and pluripotency. These genes have not yet been studied within the context of MB, representing new important elements for investigation in the search for therapeutic targets, prognostic markers or for understanding of MB biology.

Relationship between molecular markers and lymphadenectomy and lymphovascular space invasion in endometrial cancer.

PURPOSE: Relationship between pathologic parameters, surgical parameters, or lymph node status with oncologic outcomes is not fully elucidated in endometrial cancer (EC). We want to investigate the molecular classification of uterine cancer in the Turkish population and its relationship between lymphadenectomy and lymph node metastasis. METHODS: In this study, 100 patients' clinical and pathologic data diagnosed with EC were analyzed. Pathologic and molecular parameters were investigated and compared them with clinical parameters. RESULTS: According to the molecular analysis, 16 patients (16%) had p53 mutation, 3 patients (3%) were classified as POLE mutant group, 38 (38%) patients in the MSI group, and the remaining 43 patients (43%) into the no specific mutation profile (NSMP) group. Lymph node metastasis rate was significantly higher in copy number high (CNH) group compared to the others. In the CNH group, 29 of 437 (6.6%) dissected lymph nodes had metastasis. The median OS was the highest in the POLE group (72 months) and lowest in the CNH group (36 months). CONCLUSION: Endometrial cancer patients showed significantly different overall and disease-free survival according to the molecular subtypes and it was consistent with the literature, Lymph node metastasis risk was the highest in CNH group. MSI status is important for the lymph node metastasis risk but not all abnormalities, especially PMS2 and MLH1 expression changes showed the highest risk.

ROS1 genomic rearrangements are rare actionable drivers in microsatellite stable colorectal cancer.

c-Ros oncogene 1, receptor tyrosine kinase (ROS1) genomic rearrangements have been reported previously in rare cases of colorectal cancer (CRC), yet little is known about the frequency, molecular characteristics, and therapeutic vulnerabilities of ROS1-driven CRC. We analyzed a clinical dataset of 40 589 patients with CRC for ROS1 genomic rearrangements and their associated genomic characteristics (Foundation Medicine, Inc [FMI]). We moreover report the disease course and treatment response of an index patient with ROS1-rearranged metastatic CRC. ROS1 genomic rearrangements were identified in 34 (0.08%) CRC samples. GOPC-ROS1 was the most common ROS1 fusion identified (11 samples), followed by TTC28-ROS1 (3 samples). Four novel 5' gene partners of ROS1 were identified (MCM9, SRPK1, EPHA6, P4HA1). Contrary to previous reports on fusion-positive CRC, ROS1-rearrangements were found exclusively in microsatellite stable (MSS) CRCs. KRAS mutations were significantly less abundant in ROS1-rearranged vs ROS1 wild type cases. The index patient presented with chemotherapy-refractory metastatic right-sided colon cancer harboring GOPC-ROS1. Molecularly targeted treatment with crizotinib induced a rapid and sustained partial response. After 15 months on crizotinib disseminated tumor progression occurred and KRAS Q61H emerged in tissue and liquid biopsies. ROS1 rearrangements define a small, yet therapeutically actionable molecular subgroup of MSS CRC. In summary, the high prevalence of GOPC-ROS1 and noncanonical ROS1 fusions pose diagnostic challenges. We advocate NGS-based comprehensive molecular profiling of MSS CRCs that are wild type for RAS and BRAF and patient enrollment in precision trials.

Association of high-dose radiotherapy with improved survival in patients with newly diagnosed low-grade gliomas.

BACKGROUND: The radiation dose for patients with low-grade gliomas (LGGs) is controversial. The objective of this study was to investigate the impact of the radiation dose on survival for patients with LGGs and especially for molecularly defined subgroups. METHODS: Three hundred fifty-one patients with newly diagnosed LGGs from the multicenter Chinese Glioma Cooperative Group received postoperative radiotherapy (RT) in 2005-2018. The RT dose, as a continuous variable, was entered into a Cox regression model using penalized spline regression to allow for a nonlinear relationship between the RT dose and overall survival (OS) or progression-free survival (PFS). Inverse probability of treatment weighting (IPTW)-adjusted propensity scores were used to correct for potential confounders. Dose effects on survival within IDH mutation and 1p/19q codeletion defined subgroups were analyzed. RESULTS: The risk of mortality and disease progression decreased sharply until 54 Gy. High-dose RT (≥54 Gy) was associated with significantly better 5-year OS (81.7% vs 64.0%; hazard ratio [HR], 0.33; P < .001) and PFS (77.4% vs 54.5%; HR, 0.46; P < .001) than low-dose RT (<54 Gy). IPTW correction confirmed the associations (HR for OS, 0.44; P = .001; HR for PFS, 0.48; P = .003). High-dose RT was associated with longer PFS (HR, 0.25; P = .002; HR, 0.21; P = .039) and OS (HR, 0.27; P = .006; HR, 0.07; P = .017) in IDH-mutant/1p/19q noncodeleted and IDH wild-type subgroups, respectively. No significant difference in survival was observed with high-dose RT in the IDH-mutant/1p/19q codeleted subgroup. CONCLUSIONS: High-dose RT (≥54 Gy) was effective in LGGs. Patients with an IDH mutation/1p/19q noncodeletion or IDH wild-type may need to be considered for high-dose RT. LAY SUMMARY: The radiotherapy dose-response was observed in patients with low-grade gliomas, and high-dose radiotherapy (≥54 Gy) was associated with improved survival. Patients with an IDH mutation/1p/19q noncodeletion or wild-type IDH may have improved survival with the administration of high-dose radiotherapy.

Impacts of genotypic variants on survival following reoperation for recurrent glioblastoma.

INTRODUCTION: Recurrent glioblastoma (rGBM) prognosis is dismal. In the absence of effective adjuvant treatments for rGBM, re-resections remain prominent in our arsenal. This study evaluates the impact of reoperation on post-progression survival (PPS) considering rGBM genetic makeup. METHODS: To assess the genetic heterogeneity and treatment-related changes (TRC) roles in re-operated or medically managed rGBMs, we compiled demographic, clinical, histopathological, and next-generation genetic sequencing (NGS) characteristics of these tumors from 01/2005 to 10/2019. Survival data and reoperation were analyzed using conventional and random survival forest analysis (RSF). RESULTS: Patients harboring CDKN2A/B loss (p = 0.017) and KDR mutations (p = 0.031) had notably shorter survival. Reoperation or bevacizumab were associated with longer PPS (11.2 vs. 7.4-months, p = 0.006; 13.1 vs 6.2, p < 0.001). Reoperated patients were younger, had better performance status and greater initial resection. In 136/273 (49%) rGBMs undergoing re-operation, CDKN2A/B loss (p = 0.03) and KDR mutations (p = 0.02) were associated with shorter survival. In IDH-WT rGBMs with NGS data (n = 166), reoperation resulted in 7.0-month longer survival (p = 0.004) than those managed medically. This reoperation benefit was independently identified by RSF analysis. Stratification analysis revealed that EGFR-mutant, CDKN2A/B-mutant, NF1-WT, and TP53-WT rGBM IDH-WT subgroups benefit most from reoperation (p = 0.03). Lastly, whether or not TRC was prominent at re-operation does not have any significant impact on PPS (10.5 vs. 11.5-months, p = 0.77). CONCLUSIONS: Maximal safe re-resection significantly lengthens PPS regardless of genetic makeup, but reoperations are especially beneficial for IDH-WT rGBMs with EGFR and CDKN2A/B mutations with TP53-WT, and NF1-WT. Histopathology at recurrence may be an imperfect gauge of disease severity at progression and the imaging progression may be more reflective of the prognosis.

Single nCounter assay for prediction of MYCN amplification and molecular classification of medulloblastomas: a multicentric study.

PURPOSE: Medulloblastoma is the most frequent pediatric malignant brain tumor, and is divided into four main subgroups: WNT, SHH, group 3, and group 4. MYCN amplification is an important medulloblastoma prognostic biomarker. We aimed to molecular classify and predict MYCN amplification in a single assay. METHODS: It was included 209 medulloblastomas from 205 patients (Brazil, Argentina, and Portugal), divided into training (n = 50) and validation (n = 159) sets. A nCounter assay was carried out using a custom panel for molecular classification, with additional genes, including MYCN. nSolver 4.0 software and the R environment were used for profiling and MYCN mRNA analysis. MYCN amplification by FISH was performed in 64 cases. RESULTS: The 205 medulloblastomas were classified in SHH (44.9%), WNT (15.6%), group 3 (18.1%) and group 4 (21.4%). In the training set, MYCN amplification was detected in three SHH medulloblastomas by FISH, which showed significantly higher MYCN mRNA counts than non-FISH amplified cases, and a cutoff for MYCN amplification was established ([Formula: see text] + 4σ = 11,124.3). Applying this threshold value in the validation set, we identified MYCN mRNA counts above the cutoff in three cases, which were FISH validated. CONCLUSION: We successfully stratified medulloblastoma molecular subgroups and predicted MYCN amplification using a single nCounter assay without the requirement of additional biological tissue, costs, or bench time.

News in the classification of WHO 2022 bladder tumors.

The fifth-edition of World Health Organization (WHO) Classification of Tumors series for urinary and male genital tract tumors has been published, six years later the fourth-edition. In these years, new treatment approaches have been implemented and new molecular data on urological cancers are known.Morphology remains the groundwork for taxonomy of the urinary tract tumors. However, a molecular approach to classification of urothelial carcinomas and the management of selected neoplasms with new therapeutic modalities such as immunotherapy are emerging. More data are needed for the application of these advances in routine pathology practice and patient management.The 2022 World Health Organization (WHO) Classification of Tumors of the Urinary System and Male Genital Organs represents an update in classification on urinary tract tumors. It also offers new insights with regards to the grading of heterogeneous non-invasive urothelial neoplasms, the definition of inverted neoplasms, the grading of invasive urothelial carcinomas, the diversity of morphological appearance of urothelial carcinomas, the definition of precursor lesions and the lineage of differentiation of the tumors.

Integrative molecular characterisation of gallbladder cancer reveals micro-environment-associated subtypes.

BACKGROUND & AIMS: Gallbladder cancer (GBC) is the most common type of biliary tract cancer, but the molecular mechanisms involved in gallbladder carcinogenesis remain poorly understood. In this study, we applied integrative genomics approaches to characterise GBC and explore molecular subtypes associated with patient survival. METHODS: We profiled the mutational landscape of GBC tumours (whole-exome sequencing on 92, targeted sequencing on 98, in total 190 patients). In a subset (n = 45), we interrogated the matched transcriptomes, DNA methylomes, and somatic copy number alterations. We explored molecular subtypes identified through clustering tumours by genes whose expression was associated with survival in 47 tumours and validated subtypes on 34 publicly available GBC cases. RESULTS: Exome analysis revealed TP53 was the most mutated gene. The overall mutation rate was low (median 0.82 Mut/Mb). APOBEC-mediated mutational signatures were more common in tumours with higher mutational burden. Aflatoxin-related signatures tended to be highly clonal (present in ≥50% of cancer cells). Transcriptome-wide survival association analysis revealed a 95-gene signature that stratified all GBC patients into 3 subtypes that suggested an association with overall survival post-resection. The 2 poor-survival subtypes were associated with adverse clinicopathologic features (advanced stage, pN1, pM1), immunosuppressive micro-environments (myeloid-derived suppressor cell accumulation, extensive desmoplasia, hypoxia) and T cell dysfunction, whereas the good-survival subtype showed the opposite features. CONCLUSION: These data suggest that the tumour micro-environment and immune profiles could play an important role in gallbladder carcinogenesis and should be evaluated in future clinical studies, along with mutational profiles. LAY SUMMARY: Gallbladder cancer is highly fatal, and its causes are poorly understood. We evaluated gallbladder tumours to see if there were differences between tumours in genetic information such as DNA and RNA. We found evidence of aflatoxin exposure in these tumours, and immune cells surrounding the tumours were associated with survival.

The immunologic tumor microenvironment in endometrioid endometrial cancer in the morphomolecular context: mutual correlations and prognostic impact depending on molecular alterations.

OBJECTIVE: POLE-mutant, microsatellite-instable (MSI), p53-mutant and non-specific molecular profile (NSMP) are TCGA-defined molecular subgroups of endometrial cancer (EC). Hypothesizing that morphology and tumor immunology might differ depending on molecular background concerning composition and prognostic impact, we aimed to comprehensively interconnect morphologic, immunologic and molecular data. METHODS: TCGA-defined molecular groups were determined by immunohistochemistry and sequencing in n = 142 endometrioid EC. WHO-defined histopathological grading was performed. The immunologic microenvironment (iTME) was characterised by the quantification of intraepithelial and stromal populations of tumor-infiltrating lymphocytes (TIL: overall T-cells; T-Killer cells; regulatory T-cells (Treg)). Immunologic parameters were correlated with WHO-grading, TCGA-subgroups and prognosis. RESULTS: High density TIL were significantly more frequent in high-grade (G3) compared to low-grade (G1/2) EC in the whole cohort and in the subgroup of POLE-wildtype-/microsatellite-stable-EC. MSI was associated with high-level TIL-infiltration when taking into account the type of mismatch repair defect (MLH1/PMS2; MSH2/MSH6). Prognostic impact of biomarkers depended on molecular subgroups: In p53-mutant EC, Treg were independently prognostic, in NSMP, the unique independently prognostic biomarker was WHO-grading. CONCLUSIONS: EC morphology and immunology differ depending on genetics. Our study delineated two molecularly distinct subgroups of immunogenic EC characterized by high-density TIL-infiltration: MSI EC and high-grade POLE-wildtype/microsatellite-stable-EC. Prognostic impact of TIL-populations relied on TCGA-subgroups indicating specific roles for TIL depending on molecular background. In NSMP, histopathological grading was the only prognostic biomarker demonstrating the relevance of WHO-grading in an era of molecular subtyping.

Clinico-pathological significance of TCGA classification and SWI/SNF proteins expression in undifferentiated/dedifferentiated endometrial carcinoma: A possible prognostic risk stratification.

BACKGROUND: Undifferentiated/dedifferentiated endometrial carcinoma (UEC/DDEC) is a heterogeneous entity, which may show any of the TCGA molecular signatures and loss of the switch/sucrose nonfermentable (SWI/SNF) proteins expression. AIM: To assess the clinico-pathological significance of the TCGA molecular groups and SWI/SNF proteins expression in UEC/DDEC, through a quantitative systematic review. METHODS: Electronic databases were searched for all studies assessing the TCGA molecular groups, i.e. POLE-mutant, mismatch repair-deficient (MMRd), p53-abnormal (p53abn) and no specific molecular profile (NSMP), and/or the SWI/SNF proteins (SMARCA4/BRG1, SMARCB1/INI1, ARID1B) expression in UEC/DDEC. Student t-test, Fisher's exact test and Kaplan-Meier survival analysis with long-rank test were used to assess differences among groups; a p-value<0.05 was considered significant. RESULTS: Eight studies were included in the systematic review. Among the TCGA groups, the mean patient age was significantly higher in the p53abn group than in the NSMP group (p = 0.048). The POLE-mutant group showed advanced FIGO stage (III-IV) significantly less commonly than the NSMP (p = 0.003) and MMRd (p = 0.008) groups, and a significantly better prognosis than the NSMP (p = 0.007), MMRd (p = 0.011) and p53abn (p = 0.045) groups.The SWI/SNF-deficient cases showed a significantly worse prognosis than the SWI/SNF-intact cases (p = 0.010), while no significant differences were found regarding patient age and FIGO stage. CONCLUSIONS: Among UEC/DDEC, POLE-mutant cases show good prognosis, while SWI/SNF-deficient cases show poor prognosis. The other TCGA molecular subtypes seem to be characterized by an intermediate biological behaviour. On this account, UEC/DDEC patients might be subdivided into three risk groups based on POLE and SWI/SNF status. Further studies are necessary in this field.

Deciphering the Transcriptomic Heterogeneity of Duodenal Coeliac Disease Biopsies.

Coeliac disease (CD) is a clinically heterogeneous autoimmune disease with variable presentation and progression triggered by gluten intake. Molecular or genetic factors contribute to disease heterogeneity, but the reasons for different outcomes are poorly understood. Transcriptome studies of tissue biopsies from CD patients are scarce. Here, we present a high-resolution analysis of the transcriptomes extracted from duodenal biopsies of 24 children and adolescents with active CD and 21 individuals without CD but with intestinal afflictions as controls. The transcriptomes of CD patients divide into three groups-a mixed group presenting the control cases, and CD-low and CD-high groups referring to lower and higher levels of CD severity. Persistence of symptoms was weakly associated with subgroup, but the highest marsh stages were present in subgroup CD-high, together with the highest cell cycle rates as an indicator of virtually complete villous atrophy. Considerable variation in inflammation-level between subgroups was further deciphered into immune cell types using cell type de-convolution. Self-organizing maps portrayal was applied to provide high-resolution landscapes of the CD-transcriptome. We find asymmetric patterns of miRNA and long non-coding RNA and discuss the effect of epigenetic regulation. Expression of genes involved in interferon gamma signaling represent suitable markers to distinguish CD from non-CD cases. Multiple pathways overlay in CD biopsies in different ways, giving rise to heterogeneous transcriptional patterns, which potentially provide information about etiology and the course of the disease.

Identification and validation of tumour microenvironment-based immune molecular subgroups for gastric cancer: immunotherapeutic implications.

BACKGROUND: Immunotherapy could trigger durable response in advanced gastric cancer, but it only benefits a minority of patients. We aimed to propose a robust molecular classification of gastric cancer microenvironment to identify ideal candidates for tailoring effective immunotherapy. METHODS: A training cohort of 375 gastric cancer samples with RNA sequencing data was analysed. We virtually microdissected tumour, stromal, and immune cell gene expression patterns employing a non-negative matrix factorization algorithm. These expression patterns were annotated using immune- and stromal-related gene signatures. Validation of immunogenomic classification was performed across six microarray datasets of 1406 samples. RESULTS: We found approximately half of gastric cancer samples to have higher immune cell infiltrates, PD-L1 expression, markers of cytolytic activity, and fewer copy number aberrations (all P < 0.05). We termed this group of tumours the Immune Class, which incorporated two components, namely Immune Activation and Immunosuppressive Subtype, according to immunosuppressive or activated microenvironment. Immune Activation Subtype was associated with improved survival in multivariate survival analysis and shared similar genomic characteristics with responders of anti-PD-1 therapy. Immunosuppressive Subtype featured high immune infiltration, stromal enrichment, and transforming growth factor (TGF)-ß signalling pathway activation and correlated with non-responsiveness signature of checkpoint blockade therapy, which might be suitable for anti-PD-L1 and anti-TGF-ß combined therapy. CONCLUSIONS: We proposed and independently validated three reproducible immune molecular subtypes of gastric cancer, which may provide implications for patient selection of immunotherapy.

Risk-adapted therapy and biological heterogeneity in pineoblastoma: integrated clinico-pathological analysis from the prospective, multi-center SJMB03 and SJYC07 trials.

Pineoblastoma is a rare embryonal tumor of childhood that is conventionally treated with high-dose craniospinal irradiation (CSI). Multi-dimensional molecular evaluation of pineoblastoma and associated intertumoral heterogeneity is lacking. Herein, we report outcomes and molecular features of children with pineoblastoma from two multi-center, risk-adapted trials (SJMB03 for patients ≥ 3 years; SJYC07 for patients < 3 years) complemented by a non-protocol institutional cohort. The clinical cohort consisted of 58 patients with histologically diagnosed pineoblastoma (SJMB03 = 30, SJYC07 = 12, non-protocol = 16, including 12 managed with SJMB03-like therapy). The SJMB03 protocol comprised risk-adapted CSI (average-risk = 23.4 Gy, high-risk = 36 Gy) with radiation boost to the primary site and adjuvant chemotherapy. The SJYC07 protocol consisted of induction chemotherapy, consolidation with focal radiation (intermediate-risk) or chemotherapy (high-risk), and metronomic maintenance therapy. The molecular cohort comprised 43 pineal parenchymal tumors profiled by DNA methylation array (n = 43), whole-exome sequencing (n = 26), and RNA-sequencing (n = 16). Respective 5-year progression-free survival rates for patients with average-risk or high-risk disease on SJMB03 or SJMB03-like therapy were 100% and 56.5 ± 10.3% (P = 0.007); respective 2-year progression-free survival rates for those with intermediate-risk or high-risk disease on SJYC07 were 14.3 ± 13.2% and 0% (P = 0.375). Of patients with average-risk disease treated with SJMB03/SJMB03-like therapy, 17/18 survived without progression. DNA-methylation analysis revealed four clinically relevant pineoblastoma subgroups: PB-A, PB-B, PB-B-like, and PB-FOXR2. Pineoblastoma subgroups differed in age at diagnosis, propensity for metastasis, cytogenetics, and clinical outcomes. Alterations in the miRNA-processing pathway genes DICER1, DROSHA, and DGCR8 were recurrent and mutually exclusive in PB-B and PB-B-like subgroups; PB-FOXR2 samples universally overexpressed the FOXR2 proto-oncogene. Our findings suggest superior outcome amongst older children with average-risk pineoblastoma treated with reduced-dose CSI. The identification of biologically and clinically distinct pineoblastoma subgroups warrants consideration of future molecularly-driven treatment protocols for this rare pediatric brain tumor entity.

Medulloblastoma: "Onset of the molecular era".

Among brain tumors, Medulloblastoma (MB) is one of the most common, malignant, pediatric tumors of the cerebellum. It accounts for ~20% of all childhood central nervous system (CNS) tumors. Despite, tremendous advances in drug development processes, as well as novel drugs for MB the morbidity and mortality rates, remain high. Craniospinal radiation, high-dose chemotherapy, and surgical resection are the primary therapeutic strategies. Tremendous progress in the field of "genomics" with vast amounts of data has led to the identification of four distinct molecular subgroups in medulloblastoma: WNT group, SHH group, group-III, and group-IV. The identification of these subgroups has led to individualized treatment strategies for each subgroup. Here, we discuss the various molecular subgroups of medulloblastoma as well as the differences between them. We also highlight the latest treatment strategies available for medulloblastoma.

Is H3K27me3 status really a strong prognostic indicator for pediatric posterior fossa ependymomas? A single surgeon, single center experience.

PURPOSE: Posterior fossa ependymomas (PFE) are among the most frequently occurring solid tumors in children. Their definitive treatment is surgical excision and adjuvant radio-chemotherapy. This study aimed to investigate prognostic effects of age, H3K27me3 status, extent of resection, radiation treatment (RT), Ki67 index, WHO grade, and ATRX and H3K27M mutations in PFE patients. METHODS: This retrospective study included 42 pediatric patients with PFE who had undergone operation at our institution between 1996 and 2018. Patient demographics and treatment information were obtained from patient notes. Information on radiological location of tumors (median vs paramedian), extent of tumor resection, and recurrence was obtained from preoperative and postoperative magnetic resonance imaging. Formalin-fixed paraffin-embedded tumor samples were evaluated for H3K27me3 immunostaining, Ki67 index, WHO grades, and ATRX and H3K27M mutations. Tumor samples with global reduction in H3K27me3 were grouped as posterior fossa ependymoma group A (PFA) and those with H3K27me3 nuclear immunopositivity as posterior fossa ependymoma group B (PFB). We evaluated the cohort's 5-year progression-free survival (PFS) and overall survival (OS). RESULTS: There were 20 (47.6%) female and 22 (52.4%) male patients in the cohort. The mean age of patients was 4.4 (range, 0.71-14.51) years. Overall, tumors in 31 (73.8%) and 11 (26.2%) patients were found to be PFA and PFB, respectively. There was no statistically significant age or sex difference between PFA and PFB. All patients received chemotherapy, whereas only 28 (66.6%) received RT. The WHO grades of PFA were statistically higher than those of PFB. There was no significant difference between PFA and PFB in terms of extent of resection, disease recurrence, and survival parameters. Nine of 42 tumor samples had ATRX mutations. One patient with PFA showed H3K27M mutation. Age, WHO grade, H3K27me3 status, and RT had no effect on patients' PFS and OS. Patients with total surgical excisions had significantly better PFS and OS rates. Those with Ki67 < 50% also had better OS rates. CONCLUSIONS: Determining H3K27me3 status by immunohistochemistry is a widely accepted method for molecular subgrouping of PFEs. Most of the reports in the literature state that molecular subgroups of PFEs have significantly different clinical outcomes. However, in our present series, we have shown that the extent of surgical excision is still the most important prognostic indicator in PFEs. We also conclude that the prognostic effect of H3K27me3 status-based molecular subgrouping may be minimized with a more aggressive surgical strategy followed in PFAs.

Subgroup-specific outcomes of children with malignant childhood brain tumors treated with an irradiation-sparing protocol.

PURPOSE: Molecular subgroups of pediatric brain tumors associated with divergent biological, clinical, and prognostic features have been identified. However, data regarding the impact of subgroup affiliation on the outcome of children with malignant brain tumors treated with radiation-sparing protocol is limited. We report long-term clinical outcomes and the molecular subgroups of malignant brain tumors in young children whose first-line treatment was high-dose chemotherapy without irradiation. METHODS: Tumor subclassification was performed using the Illumina HumanMethylation450 BeadChip (450k) genome-wide methylation array profiling platform. Clinical information was obtained from chart review. RESULTS: Methylation array profiling yielded information on molecular subgroups in 22 children. Median age at surgery was 26 months (range 1-119 months). Among medulloblastomas (MB), all 6 children in the infant sonic hedgehog (SHH) subgroup were long-term survivors, whereas all 4 children in subgroup 3 MB died. There was one long-term survivor in subgroup 4 MB. One out of five children with ependymoma was a long-term survivor (RELPOS). Both children with primitive neuroectodermal tumors died. One child with ATRT TYR and one child with choroid plexus carcinoma were long-term survivors. CONCLUSIONS: The efficacy of high-dose chemotherapy radiation-sparing treatment appears to be confined to favorable molecular subgroups of pediatric brain tumors, such as infant SHH MB. Identification of molecular subgroups that benefit from radiation-sparing therapy will aid in the design of prospective, "precision medicine"-driven clinical trials.

Newly Diagnosed Metastatic Intracranial Ependymoma in Children: Frequency, Molecular Characteristics, Treatment, and Outcome in the Prospective HIT Series.

BACKGROUND: Data on frequency, clinical presentation, and outcome of primary metastatic intracranial ependymoma in children are scarce. PATIENTS AND METHODS: Prospective data on patients younger than 21 years with metastatic intracranial ependymoma at first diagnosis, registered from 2001 to 2014 in the HIT-2000 trial and the HIT-2000 Interim Registry, were analyzed. RESULTS: Of 453 registered patients with intracranial ependymoma and central neuropathology review, initial staging included spinal magnetic resonance imaging in all patients and lumbar cerebrospinal fluid (CSF) analysis in 402 patients. Ten patients (2.2%) had metastatic disease, including three with microscopic CSF positivity only (M1 metastasis stage, 0.7% of patients with CSF staging). Location of the primary tumor was supratentorial in four patients (all supratentorial RELA-fused ependymoma [ST-EPN-RELA]) and within the posterior fossa in five patients (posterior fossa ependymoma type A [PF-EPN-A], n = 4; posterior fossa ependymoma not further classifiable, n = 1), and multifocal in one patient.All four patients with ST-EPN-RELA were alive in first or second complete remission (CR) 7.5-12.3 years after diagnosis. All four patients with macroscopic metastases of posterior fossa or multifocal ependymoma died. Three patients with initial M1 stage (ST-EPN-RELA, n = 1; PF-EPN-A, n = 2) received chemotherapy and local irradiation and were alive in second or third CR 3.0-9.7 years after diagnosis. Progression-free and overall survival of the entire cohort at 5 years was 13% (±6%), and 58% (±16%), respectively. CONCLUSION: Primary metastatic disease is rare in children with intracranial ependymoma. Prognosis may depend on molecular subgroup and extent of dissemination, and relevance of CSF analysis for initial staging remains to be clarified. IMPLICATIONS FOR PRACTICE: Childhood ependymoma presenting with metastasis at first diagnosis is very rare with a frequency of 2.4% in this population-based, well-characterized cohort. Detection of microscopic metastases in the cerebrospinal fluid was extremely rare, and impact on prognosis and respective treatment decision on irradiation field remains unclear. Initial metastatic presentation occurs in both supratentorial RELA-fused ependymoma and posterior fossa ependymoma. Prognosis may differ according to extent of metastasis and biological subgroup, with poor prognosis in diffusely spread metastatic posterior fossa ependymoma even after combination therapy with both intensive chemotherapy and craniospinal irradiation, which may help to guide individual therapeutic decisions for future patients.

Prognostic stratification of muscle invasive urothelial carcinomas using limited immunohistochemical panel of Gata3 and cytokeratins 5/6, 14 and 20.

BACKGROUND: Genomic studies have delineated distinct molecular subgroups of urothelial carcinomas whose prognostic impact extends beyond traditional stage and grade groupings. The 'basal' subgroup shows increased gene expression levels of KRT5, KRT6, and KRT14 and low expression levels of GATA binding protein 3, and is associated with an extremely poor outcome. Identification of this subset is necessary for improved patient management and research on targeted therapies. We aimed to assess the prognostic utility of immunohistochemistry (IHC) for basal markers: cytokeratin 5/6 (CK5/6) and 14 (CK14), and luminal markers: cytokeratin 20 (CK20) and Gata3 in muscle invasive urothelial carcinomas (MIBC). MATERIALS AND METHODS: Study was of retrospective design (2014-2017). All chemotherapy naïve patients of MIBC undergoing radical cystectomy were included. IHC was performed on formalin fixed paraffin-embedded whole tumor sections. RESULTS: Among 40 cases of MIBC included, 45% (18/40) were positive for one or both basal markers, 37.5% (15/40) were positive for one or both luminal markers, while 15% (6/40) were positive for both basal and luminal markers. One case did not express any of the four markers. MIBCs expressing only basal markers presented at an advanced stage with frequent squamous differentiation and showed a trend towards shorter overall survival. Gata3+ MIBCs showed the best outcome irrespective of expression of other markers, while CK14+/Gata3- MIBCs were associated with worst outcomes. Gata3-/CK14- MIBCs showed intermediate survival outcomes. CK5/6, CK20 and p53 expression did not significantly correlate with outcome. CONCLUSION: IHC for Gata-3 and CK14 stratified MIBC into distinct prognostic subsets.