Investigação do perfil molecular do osteossarcoma em crianças e adolescentes de diferentes grupos etários utilizando painel de sequenciamento de nova geração
Data
2021-07-21
Autores
Guimarães, Giovanna Manga [UNIFESP]
Orientadores
de Toledo, Silvia Regina Caminada
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Introdução: O osteossarcoma (OS) é a mais comum neoplasia primária dos ossos entre crianças e adolescentes, apresentando alto potencial metastático, resistência ao tratamento e, em certos casos, seu desenvolvimento pode relacionar-se à presença de mutações em linhagem germinativa. Apesar do OS ocorrer principalmente durante a fase de estirão de crescimento, na segunda década de vida, médicos têm apontado para um segundo grupo, mais raro, de crianças que desenvolvem OS antes dos 10 anos de idade. Assim, a identificação de diferentes grupos de risco e suas particularidades clínicas e biológicas faz-se necessária para uma melhor abordagem terapêutica. Objetivo: identificar e comparar, por meio de sequenciamento de nova geração (NGS), as alterações genéticas presentes em amostras de OS e sangue de pacientes diagnosticados antes e durante a segunda década de vida. Metodologia: Foram selecionadas 84 amostras tumorais de 84 pacientes, diagnosticados e tratados no Instituto de Oncologia Pediátrica (IOP/GRAACC – UNIFESP), 33 deles pertencentes à primeira década e 51, à segunda década de vida. As amostras foram submetidas a um painel de NGS desenhado especificamente para as principais alterações dos tumores da infância e adolescência, chamado Oncomine Childhood Cancer Research Assay (OCCRA®). Onze pacientes tiveram suas amostras de sangue também sequenciadas para confirmação da presença da mutação nas células de linhagem germinativa. As variáveis clínicas e as características histopatológicas dos tumores foram coletadas e associadas aos achados moleculares. Resultados: Quarenta e duas (50%) amostras de OS apresentaram alguma variante somática, sendo as CNVs o principal evento genético encontrado. De todas as variantes detectadas, 89,3% foram classificadas como patogênicas. As variantes nos genes TP53, MYC, CDK4, RB1 e PDGFRA foram as mais observadas. CNVs no gene MYC foram mais frequentes em tumores de pacientes diagnosticados antes dos 10 anos (X21= 5.18, p = 0.023). Adicionalmente, aqueles diagnosticados durante a segunda década apresentaram maior porcentagem de variantes somáticas e germinativas. Variantes germinativas foram encontradas em 5 dos 11 (45,5%) pacientes analisados. Conclusão: nossos resultados sugerem que pacientes diagnosticados com OS na primeira e segunda década de vida podem apresentar padrões de alterações moleculares distintos, sendo as CNVs do gene MYC mais frequentes naqueles diagnosticados antes dos 10 anos; ainda, variantes somáticas nos genes TP53, MYC, CDK4, RB1 e PDGFRA foram identificadas em ambos os grupos. As investigações germinativas apontam que o acompanhamento genético clínico de pacientes diagnosticados com OS deve ser uma abordagem a ser considerada.
Background: Osteosarcoma (OS) is the most common primary bone tumor among children and adolescents, presenting high metastatic potential and resistance to treatment, thus, new therapeutic approaches are needed. Although OS usually occurs during the pubertal growth spurt, in the second decade of life, researchers and clinicians have pointed to a second, rarer group of patients that develops OS before 10 years old. Additionally, recent investigations have shown that in some cases, OS tumorigenesis is possibly related with the presence of germline mutations. Hence, the necessity of investigating not just OS molecular signatures that could be used as prognostic markers or therapeutic targets, but also the possible presence of distinctive risk groups and their clinical and biological differences is urgent. Objective: To access and compare, through NGS strategy, the genetic alterations present in OS and blood samples from patients diagnosed before and during the second decade of life. Methods: We selected 84 OS samples from 84 patients diagnosed and treated at the Pediatric Oncology Institute (IOP/GRAACC – UNIFESP), 33 of them diagnosed under the age of 10 and 51, during the second decade of life. All samples were submitted to targeted sequencing using a custom NGS panel design specifically for the main alterations described in childhood and adolescence neoplasms, named Oncomine Childhood Cancer Research Assay (OCCRA©). Eleven patients also had their blood samples sequenced to confirm the presence of the respective mutations in the germline cells. Clinical variables and tumor histopathological characteristics were also collected and correlated with the molecular findings. Results: Of all OS samples, 42 (50%) presented some somatic genetic variant, CNVs being the most common genetic event. Of all variants reported, 89.3% were classified as pathogenic. Variants in TP53, MYC, CDK4, RB1 and PDGFRA genes were the most observed genetic variants. MYC CNVs were more frequent in tumors from patients diagnosed before 10 years old (X21= 5.18, p = 0.023). Additionally, patients diagnosed during the second decade of life presented a higher percentage of somatic and germline variants. Germline variants were found in 5 of the 11 (45.5%) patients analyzed. Conclusion: our results suggest that patients diagnosed with OS during the first and second decade of life may present distinct patterns of molecular alterations, with MYC CNVs being more frequently in those diagnosed before 10 years old. Somatic variants in TP53, MYC, CDK4, RB1 and PDGFRA genes were identified in both groups. The germline analysis reinforce that the assessment of patients diagnosed with OS by a clinical geneticist is an approach that it is worth to be considered.
Background: Osteosarcoma (OS) is the most common primary bone tumor among children and adolescents, presenting high metastatic potential and resistance to treatment, thus, new therapeutic approaches are needed. Although OS usually occurs during the pubertal growth spurt, in the second decade of life, researchers and clinicians have pointed to a second, rarer group of patients that develops OS before 10 years old. Additionally, recent investigations have shown that in some cases, OS tumorigenesis is possibly related with the presence of germline mutations. Hence, the necessity of investigating not just OS molecular signatures that could be used as prognostic markers or therapeutic targets, but also the possible presence of distinctive risk groups and their clinical and biological differences is urgent. Objective: To access and compare, through NGS strategy, the genetic alterations present in OS and blood samples from patients diagnosed before and during the second decade of life. Methods: We selected 84 OS samples from 84 patients diagnosed and treated at the Pediatric Oncology Institute (IOP/GRAACC – UNIFESP), 33 of them diagnosed under the age of 10 and 51, during the second decade of life. All samples were submitted to targeted sequencing using a custom NGS panel design specifically for the main alterations described in childhood and adolescence neoplasms, named Oncomine Childhood Cancer Research Assay (OCCRA©). Eleven patients also had their blood samples sequenced to confirm the presence of the respective mutations in the germline cells. Clinical variables and tumor histopathological characteristics were also collected and correlated with the molecular findings. Results: Of all OS samples, 42 (50%) presented some somatic genetic variant, CNVs being the most common genetic event. Of all variants reported, 89.3% were classified as pathogenic. Variants in TP53, MYC, CDK4, RB1 and PDGFRA genes were the most observed genetic variants. MYC CNVs were more frequent in tumors from patients diagnosed before 10 years old (X21= 5.18, p = 0.023). Additionally, patients diagnosed during the second decade of life presented a higher percentage of somatic and germline variants. Germline variants were found in 5 of the 11 (45.5%) patients analyzed. Conclusion: our results suggest that patients diagnosed with OS during the first and second decade of life may present distinct patterns of molecular alterations, with MYC CNVs being more frequently in those diagnosed before 10 years old. Somatic variants in TP53, MYC, CDK4, RB1 and PDGFRA genes were identified in both groups. The germline analysis reinforce that the assessment of patients diagnosed with OS by a clinical geneticist is an approach that it is worth to be considered.
Descrição
Citação
GUIMARÃES, G. M. Investigação do perfil molecular do osteossarcoma em crianças e adolescentes de diferentes grupos etários utilizando painel de sequenciamento de nova geração. São Paulo, 2021. 96 p. Dissertação (Mestrado em Biologia Estrutural e Funcional) - Universidade Federal de São Paulo, Escola Paulista de Medicina. São Paulo, 2021