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Sökning: WFRF:(Mitra Shamik)

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1.
  • Aine, Mattias, et al. (författare)
  • Molecular analyses of triple-negative breast cancer in the young and elderly
  • 2021
  • Ingår i: Breast cancer research : BCR. - : Springer Science and Business Media LLC. - 1465-5411 .- 1465-542X. ; 23:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Breast cancer in young adults has been implicated with a worse outcome. Analyses of genomic traits associated with age have been heterogenous, likely because of an incomplete accounting for underlying molecular subtypes. We aimed to resolve whether triple-negative breast cancer (TNBC) in younger versus older patients represent similar or different molecular diseases in the context of genetic and transcriptional subtypes and immune cell infiltration.PATIENTS AND METHODS: In total, 237 patients from a reported population-based south Swedish TNBC cohort profiled by RNA sequencing and whole-genome sequencing (WGS) were included. Patients were binned in 10-year intervals. Complimentary PD-L1 and CD20 immunohistochemistry and estimation of tumor-infiltrating lymphocytes (TILs) were performed. Cases were analyzed for differences in patient outcome, genomic, transcriptional, and immune landscape features versus age at diagnosis. Additionally, 560 public WGS breast cancer profiles were used for validation.RESULTS: Median age at diagnosis was 62 years (range 26-91). Age was not associated with invasive disease-free survival or overall survival after adjuvant chemotherapy. Among the BRCA1-deficient cases (82/237), 90% were diagnosed before the age of 70 and were predominantly of the basal-like subtype. In the full TNBC cohort, reported associations of patient age with changes in Ki67 expression, PIK3CA mutations, and a luminal androgen receptor subtype were confirmed. Within DNA repair deficiency or gene expression defined molecular subgroups, age-related alterations in, e.g., overall gene expression, immune cell marker gene expression, genetic mutational and rearrangement signatures, amount of copy number alterations, and tumor mutational burden did, however, not appear distinct. Similar non-significant associations for genetic alterations with age were obtained for other breast cancer subgroups in public WGS data. Consistent with age-related immunosenescence, TIL counts decreased linearly with patient age across different genetic TNBC subtypes.CONCLUSIONS: Age-related alterations in TNBC, as well as breast cancer in general, need to be viewed in the context of underlying genomic phenotypes. Based on this notion, age at diagnosis alone does not appear to provide an additional layer of biological complexity above that of proposed genetic and transcriptional phenotypes of TNBC. Consequently, treatment decisions should be less influenced by age and more driven by tumor biology.
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2.
  • Betancourt, Lazaro Hiram, et al. (författare)
  • Improved survival prognostication of node-positive malignant melanoma patients utilizing shotgun proteomics guided by histopathological characterization and genomic data
  • 2019
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Metastatic melanoma is one of the most common deadly cancers, and robust biomarkers are still needed, e.g. to predict survival and treatment efficiency. Here, protein expression analysis of one hundred eleven melanoma lymph node metastases using high resolution mass spectrometry is coupled with in-depth histopathology analysis, clinical data and genomics profiles. This broad view of protein expression allowed to identify novel candidate protein markers that improved prediction of survival in melanoma patients. Some of the prognostic proteins have not been reported in the context of melanoma before, and few of them exhibit unexpected relationship to survival, which likely reflects the limitations of current knowledge on melanoma and shows the potential of proteomics in clinical cancer research.
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3.
  • Cabrita, Rita, et al. (författare)
  • Tertiary lymphoid structures improve immunotherapy and survival in melanoma
  • 2020
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 577:7791, s. 561-565
  • Tidskriftsartikel (refereegranskat)abstract
    • Checkpoint blockade therapies that reactivate tumour-associated T cells can induce durable tumour control and result in the long-term survival of patients with advanced cancers1. Current predictive biomarkers for therapy response include high levels of intratumour immunological activity, a high tumour mutational burden and specific characteristics of the gut microbiota2,3. Although the role of T cells in antitumour responses has thoroughly been studied, other immune cells remain insufficiently explored. Here we use clinical samples of metastatic melanomas to investigate the role of B cells in antitumour responses, and find that the co-occurrence of tumour-associated CD8+ T cells and CD20+ B cells is associated with improved survival, independently of other clinical variables. Immunofluorescence staining of CXCR5 and CXCL13 in combination with CD20 reveals the formation of tertiary lymphoid structures in these CD8+CD20+ tumours. We derived a gene signature associated with tertiary lymphoid structures, which predicted clinical outcomes in cohorts of patients treated with immune checkpoint blockade. Furthermore, B-cell-rich tumours were accompanied by increased levels of TCF7+ naive and/or memory T cells. This was corroborated by digital spatial-profiling data, in which T cells in tumours without tertiary lymphoid structures had a dysfunctional molecular phenotype. Our results indicate that tertiary lymphoid structures have a key role in the immune microenvironment in melanoma, by conferring distinct T cell phenotypes. Therapeutic strategies to induce the formation of tertiary lymphoid structures should be explored to improve responses to cancer immunotherapy.
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4.
  • Cabrita, Rita, et al. (författare)
  • Tertiary lymphoid structures improve immunotherapy and survival in melanoma.
  • 2020
  • Ingår i: Nature. - : Nature Publishing Group. - 1476-4687 .- 0028-0836. ; 577:7791, s. 561-565
  • Tidskriftsartikel (refereegranskat)abstract
    • Checkpoint blockade therapies that reactivate tumour-associated T cells can induce durable tumour control and result in the long-term survival of patients with advanced cancers1. Current predictive biomarkers for therapy response include high levels of intratumour immunological activity, a high tumour mutational burden and specific characteristics of the gut microbiota2,3. Although the role of T cells in antitumour responses has thoroughly been studied, other immune cells remain insufficiently explored. Here we use clinical samples of metastatic melanomas to investigate the role of B cells in antitumour responses, and find that the co-occurrence of tumour-associated CD8+ T cells and CD20+ B cells is associated with improved survival, independently of other clinical variables. Immunofluorescence staining of CXCR5 and CXCL13 in combination with CD20 reveals the formation of tertiary lymphoid structures in these CD8+CD20+ tumours. We derived a gene signature associated with tertiary lymphoid structures, which predicted clinical outcomes in cohorts of patients treated with immune checkpoint blockade. Furthermore, B-cell-rich tumours were accompanied by increased levels of TCF7+ naive and/or memory T cells. This was corroborated by digital spatial-profiling data, in which T cells in tumours without tertiary lymphoid structures had a dysfunctional molecular phenotype. Our results indicate that tertiary lymphoid structures have a key role in the immune microenvironment in melanoma, by conferring distinct T cell phenotypes. Therapeutic strategies to induce the formation of tertiary lymphoid structures should be explored to improve responses to cancer immunotherapy.
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5.
  • Cabrita, Rita, et al. (författare)
  • The Role of PTEN Loss in Immune Escape, Melanoma Prognosis and Therapy Response
  • 2020
  • Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 12:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Checkpoint blockade therapies have changed the clinical management of metastatic melanoma patients considerably, showing survival benefits. Despite the clinical success, not all patients respond to treatment or they develop resistance. Although there are several treatment predictive biomarkers, understanding therapy resistance and the mechanisms of tumor immune evasion is crucial to increase the frequency of patients benefiting from treatment. The PTEN gene is thought to promote immune evasion and is frequently mutated in cancer and melanoma. Another feature of melanoma tumors that may affect the capacity of escaping T-cell recognition is melanoma cell dedifferentiation characterized by decreased expression of the microphtalmia-associated transcription factor (MITF) gene. In this study, we have explored the role of PTEN in prognosis, therapy response, and immune escape in the context of MITF expression using immunostaining and genomic data from a large cohort of metastatic melanoma. We confirmed in our cohort that PTEN alterations promote immune evasion highlighted by decreased frequency of T-cell infiltration in such tumors, resulting in a worse patient survival. More importantly, our results suggest that dedifferentiated PTEN negative melanoma tumors have poor patient outcome, no T-cell infiltration, and transcriptional properties rendering them resistant to targeted- and immuno-therapy.
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6.
  • Glodzik, Dominik, et al. (författare)
  • Comprehensive molecular comparison of BRCA1 hypermethylated and BRCA1 mutated triple negative breast cancers
  • 2020
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Homologous recombination deficiency (HRD) is a defining characteristic in BRCA-deficient breast tumors caused by genetic or epigenetic alterations in key pathway genes. We investigated the frequency of BRCA1 promoter hypermethylation in 237 triple-negative breast cancers (TNBCs) from a population-based study using reported whole genome and RNA sequencing data, complemented with analyses of genetic, epigenetic, transcriptomic and immune infiltration phenotypes. We demonstrate that BRCA1 promoter hypermethylation is twice as frequent as BRCA1 pathogenic variants in early-stage TNBC and that hypermethylated and mutated cases have similarly improved prognosis after adjuvant chemotherapy. BRCA1 hypermethylation confers an HRD, immune cell type, genome-wide DNA methylation, and transcriptional phenotype similar to TNBC tumors with BRCA1-inactivating variants, and it can be observed in matched peripheral blood of patients with tumor hypermethylation. Hypermethylation may be an early event in tumor development that progress along a common pathway with BRCA1-mutated disease, representing a promising DNA-based biomarker for early-stage TNBC.
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7.
  • Lauss, Martin, et al. (författare)
  • Mutational and putative neoantigen load predict clinical benefit of adoptive T cell therapy in melanoma
  • 2017
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Adoptive T-cell therapy (ACT) is a highly intensive immunotherapy regime that has yielded remarkable response rates and many durable responses in clinical trials in melanoma; however, 50-60% of the patients have no clinical benefit. Here, we searched for predictive biomarkers to ACT in melanoma. Whole exome-and transcriptome sequencing and neoantigen prediction were applied to pre-treatment samples from 27 patients recruited to a clinical phase I/II trial of ACT in stage IV melanoma. All patients had previously progressed on other immunotherapies. We report that clinical benefit is associated with significantly higher predicted neoantigen load. High mutation and predicted neoantigen load are significantly associated with improved progression-free and overall survival. Further, clinical benefit is associated with the expression of immune activation signatures including a high MHC-I antigen processing and presentation score. These results improve our understanding of mechanisms behind clinical benefit of ACT in melanoma.
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8.
  • Mitra, Shamik, et al. (författare)
  • Amplification of ERBB2 (HER2) in embryonal rhabdomyosarcoma : A potential treatment target in rare cases?
  • 2022
  • Ingår i: Genes, Chromosomes and Cancer. - : John Wiley & Sons. - 1045-2257 .- 1098-2264. ; 61:1, s. 5-9
  • Tidskriftsartikel (refereegranskat)abstract
    • The ERBB2 gene encodes a receptor tyrosine kinase also known as HER2. The gene is amplified and overexpressed in one-fifth of breast carcinomas; patients with such tumors benefit from targeted treatment with trastuzumab or other drugs blocking the receptor. In addition, ERBB2 has been shown to be amplified and/or overexpressed in a variety of other malignancies. Notably, both alveolar and embryonal rhabdomyosarcoma (RMS), especially in children, often show increased expression of ERBB2. Although high-level amplification of the gene has not been described in RMS, its frequent expression at the cell surface of RMS cells has been exploited for chimeric antigen receptor T-cell (CAR T)-based treatment strategies. We here describe two cases of pediatric, fusion-negative embryonal RMS with high-level amplification of the ERBB2 gene. One patient is currently treated with conventional chemotherapy for a recently detected standard risk RMS, whereas the other patient died from metastatic disease. Both tumors displayed focal amplicons (210 and 274 Kb, respectively) in chromosome band 17q12, with proximal and distal borders corresponding to those typically seen in breast cancer. In both tumors, the ERBB2 amplicon correlated with high expression at the RNA and protein levels. Thus, breast cancer-like ERBB2 amplification is a very rare, but recurrent feature of pediatric RMS, and should be exploited as an alternative treatment target.
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9.
  • Mitra, Shamik, et al. (författare)
  • Analysis of DNA methylation patterns in the tumor immune microenvironment of metastatic melanoma
  • 2020
  • Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 14:5, s. 933-950
  • Tidskriftsartikel (refereegranskat)abstract
    • The presence of immune cells in the tumor microenvironment has been associated with response to immunotherapies across several cancer types, including melanoma. Despite its therapeutic relevance, characterization of the melanoma immune microenvironments remains insufficiently explored. To distinguish the immune microenvironment in a cohort of 180 metastatic melanoma clinical specimens, we developed a method using promoter CpG methylation of immune cell type-specific genes extracted from genome-wide methylation arrays. Unsupervised clustering identified three immune-methylation clusters with varying levels of immune CpG methylation that are related to patient survival. Matching protein and gene expression data further corroborated the identified epigenetic characterization. Exploration of the possible immune exclusion mechanisms at play revealed likely dependency on MITF protein level and PTEN loss-of-function events for melanomas unresponsive to immunotherapies (immune-low). To understand if melanoma tumors resemble other solid tumors in terms of immune-methylation characteristics, we explored 15 different solid tumor cohorts from TCGA. Low-dimensional projection based on immune cell type-specific methylation revealed grouping of the solid tumors in line with melanoma immune-methylation clusters rather than tumor types. Association of survival outcome with immune cell type-specific methylation differed across tumor and cell types. However, in melanomas immune-cell type-specific methylation was associated with inferior patient survival. Exploration of the immune-methylation patterns in a pan-cancer context suggested that specific immune-microenvironments might occur across the cancer spectrum. Together, our findings underscore the existence of diverse immune microenvironments, which may be informative for future immunotherapeutic applications.
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10.
  • Mitra, Shamik (författare)
  • Exploring the Molecular Landscape of Cutaneous Melanoma
  • 2020
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Cutaneous malignant melanoma (CMM) is one of the most aggressive skin malignancies with poor prognosisfor the patients with metastatic disease. Earlier studies have highlighted the existing molecular diversityamongst CMM tumors. Such diversity does not result from the malignant cells alone but a product of multitudeof complex interactions among the melanoma and non-melanoma cells in the tumor microenvironment. Thestudies included in this thesis aims to shed light on some aspects of this observed diversity, chiefly the roles ofthe tumor-enriching immune cells and melanoma cell phenotypes.In study I, we have identified immune cell-type associated DNA methylation patterns that have offered importantmolecular and prognostic information for the metastatic melanoma (MM) tumors. Additionally, these immune-methylationpatterns highlighted the existing microenvironmental resemblance among tumor types with diversetissue-of-origin. We further explored the immune-microenvironment of MM tumors using single-cell RNAsequencingderived marker genes and devised transcriptomic scores for the underlying major immune celltypesin study II. These immune cell-type scores were found to have prognostic implications and were predictiveof treatment benefit from immunotherapy. In study III, we investigated predictive biomarkers for the treatmentbenefit to adoptive T cell (ACT) therapy. Our analyses revealed that tumor mutational and putative neoantigenburden together with immune enrichment, could work as a composite biomarker to predict treatment benefitand patient survival upon treated with ACT.Plasticity of the melanoma cell phenotypes has garnered significant attention in recent times, especially as apossible mechanism of secondary resistance to targeted treatments. Epigenetic mechanisms such as DNAmethylation is well-known to play a major role in the transcriptional process and their involvement have beenhighlighted in context of cancers as well. In study IV, we analyzed the possible contribution of the DNAmethylation to modulate expression of the important melanoma-associated genes such as MITF and SOX10.Our results indicated that both these genes are likely to be transcriptionally modulated through DNA hypermethylationof their promoter regions and subsequently help the underlying cells to exhibit a more proliferative,invasive and treatment-resistant phenotype.Studies in this thesis have helped to unravel the existing molecular diversity in the CMM tumors and couldpotentially motivate the exploration of new therapeutic strategies.
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